EVALUATION OF BLACK OAT (AVENA STRIGOSA SCHREB.) GERMPLASM Except where reference is made to the work of others, the work described in this thesis is my own or was done in collaboration with my advisory committee. This thesis does not include proprietary or classified information. ________________________________________ Thomas Antony Certificate of Approval: _________________________ _________________________ David B. Weaver Edzard van Santen, Chair Professor Professor Agronomy and Soils Agronomy and Soils _______________________ _________________________ Andrew J. Price Joe F. Pittman Assistant Professor Interim Dean Agronomy and Soils Graduate School EVALUATION OF BLACK OAT (AVENA STRIGOSA SCHREB.) GERMPLASM Thomas Antony A Thesis Submitted to the Graduate Faculty of Auburn University in Partial Fulfillment of the Requirement for the Degree of Master of Science Auburn, Alabama December 17, 2007 iii EVALUATION OF BLACK OAT (AVENA STRIGOSA SCHREB.) GERMPLASM Thomas Antony Permission is granted to Auburn University to make copies of this thesis at its discretion, upon the request of individuals or institutions and at their expense. The author reserves all publication rights. ___________________________________ Signature of Author ___________________________________ Date of Graduation iv THESIS ABSTRACT EVALUATION OF BLACK OAT (AVENA STRIGOSA SCHREB.) GERMPLASM Thomas Antony Master of Science, December 17, 2007 (B.S. (Agriculture), Kerala Agricultural University, India, 2002) (B.S. (Botany), Mahatma Gandhi University, India, 1995) 156 Typed Pages Directed by Edzard van Santen Black oat has become an important winter cover crop in subtropical and temperate regions. Originating in the northern parts of Spain and Portugal, black oat cultivation has spread to different parts of the globe. Even though different in ploidy level, diploid black oat has been used in many hexaploid common oat (A. sativa L.) breeding programs as a donor parent for some desirable characters such as rust resistance. Black oat is an emerging cover crop for the Southeastern US. The only commercially available black oat cultivar in US is ?SoilSaver? released by Auburn University and USDA-ARS-NSDL in 2002. Even though SoilSaver is superior for some traits (e.g. maturity and biomass yield), some traits need further improvement. Over 100 black oat accessions are available from the USDA-ARS Small Grains Germplasm Unit at Aberdeen, Idaho, but a detailed study v of this collection is needed before they can be used in a breeding program. The objective of the study was to evaluate the entire USDA-NPGS black oat germplasm collection in the field for morphological traits and maturity and a subset for biomass and grain yield. We used 103 black oat accessions available from USDA and SoilSaver for the morphology and maturity study and 18 accessions selected based on their relative maturity compared to SoilSaver for plot biomass and grain yield trials. Among the 14 response variables measured, 12 were used for the ?Canonical Discriminant Analysis? (CDA) in morphology and maturity study. In CDA the first four canonical variates were responsible for 84 % of the total variation and when plotted the first two axes, the accession CIav 9015 was separated farthest from the rest of the accessions. This accession is extremely early maturing, has short culms but long and broad leaves. So we suspect that it may not belong to Avena strigosa Schreb., but to some other Avena species. Further karyotypic studies may be needed to ascertain our findings in this regard. For the yield trials we compared the biomass and grain yield and test weight of the selected accessions to SoilSaver at a standard seeding rate. None of the tested accessions performed better than SoilSaver at standard seeding rate consistently in all locations. The allelopathy study identified seven accessions having significantly higher radish radicle suppressive ability than SoilSaver. vi ACKNOWLEDGMENTS The author is thankful to God for all the blessings He showered upon him. The author would like to express his sincere thanks to Dr. Edzard van Santen for his guidance and encouragement during the course of study. The author also would like to extend his sincere thanks to the members of advisory committee, Dr. David B Weaver and Dr. Andrew J. Price for their help and support. He is also grateful to Dr. Steven L Noffsinger, for his day to day guidance and help in the course of research. The author also would like to acknowledge the helps of Dr. Ludovic J.A. Capo-chichi, Maria Stoll, staff of Alabama Agricultural Experiment Station and student workers who helped him in lab and field and fellow graduate students Reji, Janaki, Lakshmi, Monika and Jessica. Most of all, he would like to express his deep appreciation to his wife Manju for her love, support and encouragement. vii Style manual or journal format used: Handbook and Style Manual of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Computer software used: Microsoft Office 2003; SAS v.9 viii TABLE OF CONTENTS LIST OF TABLES.............................................................................................................. x LIST OF FIGURES .......................................................................................................... xii I. LITERATURE REVIEW Importance of cover crops ...........................................................................1 Classification and Botany ..........................................................................12 Cytogenetics...............................................................................................15 Molecular Markers.....................................................................................21 Breeding Programs.....................................................................................23 References..................................................................................................26 II. MORPHOLOGY AND MATURITY OF BLACK OATS (Avena strigosa Schreb.) Abstract .....................................................................................................37 Introduction................................................................................................38 Materials and Methods...............................................................................39 Statistical Analysis.....................................................................................41 Results and Discussion ..............................................................................43 ix Summary and Conclusions ........................................................................48 References..................................................................................................50 III. PLOT TRIALS IN BLACK OATS FOR BIOMASS, GRAIN YIELD AND TEST WEIGHT Abstract......................................................................................................69 Introduction................................................................................................70 Materials and Methods...............................................................................71 Statistical Analysis.....................................................................................73 Results and Discussion ..............................................................................74 Conclusions................................................................................................77 References..................................................................................................79 IV. ALLELOPATHY OF BLACK OAT ACCESSIONS Abstract....................................................................................................111 Introduction..............................................................................................112 Materials and Methods.............................................................................113 Results and Discussion ............................................................................114 References................................................................................................115 V. APPENDIX.................................................................................................................118 x LIST OF TABLES Table 2-1: Materials used for the morphology and maturity study ...............................53 Table 2-2: Response variables studied...........................................................................59 Table 2-3: Response variables studied and their range..................................................60 Table 2-4: Loading of Canonical Discriminant Analysis (CDA) ..................................61 Table 2-5: Variance analysis of the traits identified by canonical discriminant analysis .........................................................................................................62 Table 2-6: Traits with high correlation to CAN1 among different accessions..............63 Table 2-7: Traits with high correlation to CAN 2 among different accessions.............64 Table 2-8: Traits with high correlation to CAN 3 among different accessions.............65 Table 2-9: Traits with high correlation to CAN 4 among different accessions.............66 Table 3-1: Materials used for the Biomass and grain yield studies ...............................81 Table 3-2: Variance analysis of the biomass, grain yield and test weight of 2004-05 studies ............................................................................................82 Table 3-3: Variance analysis of the biomass, grain yield and test weight of 2004-05 studies ............................................................................................83 Table 3-4: LS means of biomass study 2004-05 at four locations.................................84 Table 3-5: LS means of biomass study 2006-07 at four locations.................................85 Table 3-6: LS means of grain yield and test weight study 2004-05 at four locations ...86 Table 3-7: LS means of grain yield study 2006-07 at four locations ............................87 Table 3-8: LS means of test weight study 2006-07 at four locations ............................88 xi Table 4-1: The allelopathic potential of different black oat accessions in comparison to SoilSaver.............................................................................117 xii LIST OF FIGURES Figure 1-1: Erosion in Alabama........................................................................................3 Figure 1-2: Erosion in Alabama........................................................................................3 Figure 2-1: Primary and secondary centers of origin of black oats ................................67 Figure 2-2: Canonical discriminant analysis scatter plot of morphology and maturity study .............................................................................................................68 Figure 3-1: Biomass study 2004-05at Gulf Coast Research and Extension center, Fairhope........................................................................................................89 Figure 3-2: Biomass study 2006-07at Gulf Coast Research and Extension center, Fairhope........................................................................................................90 Figure 3-3: Biomass study 2004-05 at Plant Breeding Unit, Tallassee ..........................91 Figure 3-4: Biomass study 2006-07 at Plant Breeding Unit, Tallassee ..........................92 Figure 3-5: Biomass study 2004-05 at Tennessee Valley Research and Extension Center, Belle Mina, Alabama.......................................................................93 Figure 3-6: Biomass study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina, Alabama........................................................................94 Figure 3-7: Biomass study 2004-05 at Wiregrass Research and Extension Center, Headland, Alabama ......................................................................................95 Figure 3-8: Biomass study 2006-07 at Prattville Agricultural Research Unit, Prattville, Alabama.......................................................................................96 Figure 3-9: Grain yield study 2004-05 at Prattville Agricultural Research Unit, Prattville, Alabama .......................................................................................97 Figure 3-10: Grain yield study 2006-07 at Prattville Agricultural Research Unit, Prattville, Alabama ......................................................................................98 xiii Figure 3-11: Grain yield study 2004-05 at Plant Breeding Unit.......................................99 Figure 3-12: Grain yield study 2006-07 at Plant Breeding Unit.....................................100 Figure 3-12: Grain yield study 2006-07 at Gulf Coast Research and Extension center, Fairhope.........................................................................101 Figure 3-13: Grain yield study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina......................................................................................102 Figure 3-14: Grain yield study 2006-07 at Wiregrass Research and Extension Center, Headland........................................................................................103 Figure 3-16: Test weight study 2004-05 at Prattville Agricultural Research Unit, Prattville .....................................................................................................104 Figure 3-17: Test weight study 2006-07 at Prattville Agricultural Research Unit, Prattville ...................................................................................................105 Figure 3-18: Test weight study 2004-05 at Plant Breeding Unit, Tallassee ...................106 Figure 3-19: Test weight study 2006-07 at Plant Breeding Unit, Tallassee ...................107 Figure 3-20: Test weight study 2006-07 at Gulf Coast Research and Extension center, Fairhope.........................................................................108 Figure 3-21: Test weight study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina ...................................................................109 Figure 3-22: Test weight study 2006-07 at Wiregrass Research and Extension Center, Headland........................................................................................110 1 I. LITERATURE REVIEW Introduction In modern sustainable agricultural systems cover crops occupy a pivotal role in no-tillage and reduced tillage crop management. They are grown to protect and improve the physical and chemical properties of soils. These crops can be utilized for various purposes such as winter cover or green manure, supplemental forage covering periods of shortages for regular crops, living mulch, and as a catch crop. Cover crops may be classified based on their taxonomic status (leguminous or non-leguminous) or growing season (winter vs. summer). Leguminous cover crops currently in use worldwide and those that show potential include white lupin (Lupinus albus L.) (Mask et al., 1993; Noffsinger et al., 1998), velvetbean [Mucuna deeringiana (Bort) Merr], jackbean [Canavalia ensiformis (L.) DC.], jumbie-bean [Leucaena leucocephala (Lam.) de Wit], wild tamarind [Lysiloma latisiliquum (L.) Benth] (Caamal-Maldonado et al., 2001), crimson clover [Trifolium incarnatum L.] and other Trifolium species, and hairy vetch [Vicia villosa Roth subsp. villosa]. Other leguminous crops are not considered cover crops per se but play an important role in crop rotations, e.g., alfalfa [Medicago sativa L.] and soybean [Glycine max. (L.) Merr]. Alfalfa, called the ?queen of the forages,? is cultivated for forage purposes as well as soil bioremediation (Anonymous, 2000). It was reported that a corn- soybean rotation enhances corn yield without additional nitrogen. (Maloney, 1999). 2 Another corn-soybean crop rotation study produced corn yields equivalent to the yield produced by the application of 144 kg N ha-1 (Omay, 1998). Some of the non-leguminous cover crops used extensively in the southeastern USA are rye (Secale cereale L.), wheat (Triticum aestivum L.), and oat (Avena sativa L.) (Bauer and Reeves, 1999). Non- leguminous cover crops with worldwide importance are black oat (Avena strigosa Shreb.) (Ceretta et al., 2002; Federizzi and Mundstock, 2004), white mustard (Sinapis alba L. subsp. alba), and rapeseed (Brassica napus L.) (Weinert et al., 2002). Benefits of growing cover crops Cover crops have been a part of agriculture for thousands of years, but they have received the serious attention of many farmers quite recently. Subtropical climates such as the southeastern USA can support plant growth 12 months of the year, provided moisture is available. Yet, the main agronomic crops such as corn (Zea mays subsp. mays), cotton (Gossypium hirsutum L.), and peanut (Arachis hypogaea L.) are grown during spring to early autumn. This leaves the ground uncovered for up to eight months of the year, particularly during the winter months with rainfalls in excess of 322 mm month-1 (NCDC, 2005) leading to severe erosion. In the southeastern USA, winter cover crops are essential in conservation tillage systems to protect soils from erosion and for improving soil productivity (Schomberg et al., 2005). They are of particular benefit in colder winter months to prevent the loss of nutrients (Ditsch et al., 1993; Kinyangi et al., 2001). A study conducted at the E.V. Smith Research Center showed that cotton yield was higher in a conservation system than in the conventional system of soil management. (Terra et al., 2005). 3 Figure 1-1: Erosion in Alabama (http://newdeal.feri.org/library/s25.htm) Figure 1-2: Erosion in Alabama (http://newdeal.feri.org/library/s24.htm) 4 Improving Physical Properties of Soil Cover crops are important in increasing the physical properties of the soil in many ways. Cover crops increase the soil organic carbon (SOC) content (Hermawan and Bomke, 1997; Liua et al., 2005) and dilute acid-extractable polysaccharides (Liua et al., 2005) in the soil. The dilute-acid-extractable polysaccharides act as active binding agents in the soil. The SOC (Hermawan and Bomke, 1997; Liua et al., 2005) and acid- extractable polysaccharides (Liua et al., 2005) increase aggregate stability of the soil, which is expressed as the increase in mean weight diameter (MWD). Winter wheat was found to increase vesicular-arbuscular mycorrhiza (VAM) inoculum potential, soil aggregation and yield of cash crops (Kabir and Koide, 2000). Glomalin, which is a glycoprotein produced by arbuscular mycorrhizal (AM) fungi, is positively correlated with the aggregate stability of the soil. Aggregate stability is measured as resistance to breakdown by wet sieving of air-dried soil samples (Wright and Upadhyaya, 1998). Living cover crop mulches which can reduce the daily maximum soil temperature may have both positive (in tropical conditions) and negative (in temperate conditions) effects on main crop growth (Chassot et al., 2001). Rainfall pattern and/or water availability may be other factors that need to be taken into consideration before starting any conservation system or cover cropping. Stored soil water was found to be reduced slightly after the incorporation of winter cover crops, which necessitates proper water budgeting if planted in arid and semi-arid areas (Mitchell et al., 1999). However, the water storage capacity of the soils was increased by the incorporation of winter cover crops into soil before the next season. 5 Cover crops can improve water quality by decreasing the amount of pesticides and nutrients percolating from the agricultural fields to the water sources. The reduced seepage of nutrients from agricultural land also reduces microbial contamination of water bodies. Increased phosphorus input can accelerate fresh water eutrophication (Carpenter et al., 1999; Sharpley et al., 2001). Nitrate leaching from the soil is a potential problem for water sources near the agricultural fields (Sainju et al., 1998). The leached nitrate can pollute groundwater by precipitation in fall and winter seasons. One of the methods to control nitrate leaching from the crop field is to plant a cover crop with an extensive root system that can translocate the available nitrogen into their roots. In a comparative study for the effectiveness of preventing nitrate leaching, cereal rye (Secale cereale L.) was found to be more effective in reducing residual NO3- and potential leaching than hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.) (Sainju et al., 1998). To prevent nitrate leaching effectively, it is important for a cover crop to have an extensive root system. In the experiment conducted by Sainju, the total mini rhizotron root count (MRC; no. roots cm-2 soil profile) of cover crops at 0 to 50 cm depth showed a positive correlation to N uptake and a negative correlation to soil NO3- concentration. (Sainju et al., 1998). The amount of nitrate leached into water bodies can be controlled by cultivating winter cereal grain cover crops in the field (Staver and Brinsfield, 1998). Soil cover can reduce the amount of pesticides reaching soil during spraying and, thus, can reduce the runoff loss of pesticides and eventual contamination of water bodies. (Silburn et al., 2002). 6 Cover crops can absorb P from the upper layers of soils and transport it in their roots to subsoil layers. Pea (Pisum sativum L. subsp. arvense), black oat (Avena strigosa Schreb) and narrow leafed lupin (Lupinus angustifolius L) were the most efficient cover crops for translocation of soil phosphorus for a 0 to 55 cm depth in oxisol soils. For the 10 to 55 cm depth pea, black oat and narrow leafed lupin were most efficient. Lupin had higher root phosphorus content without P-fertilizer application. This is due to the fact that lupin can absorb phosphorus from soil using specialized proteoid roots if the soil is deficient in phosphorus. These cluster roots release citric acid to mobilize the sparingly available P in the rhizosphere (Neumann et al., 1999). With fertilizer application, common vetch followed by hairy vetch and black oat has the highest content of root P. White lupin has the highest capacity of P accumulation in the aerial parts without P application. In the presence of P fertilizer, black oat accumulated more than 20 kg ha-1 of P on the aerial parts. Without P application black oat had the highest root dry matter content among the ten cover crops (Avena strigosa, Avena sativa, Secale cereale, Pisum sativum subsp arvense, Pisum sativum, Vicia villosa, Vicia sativa, Lupinus angustifolius L., Lupinus albus, and Triticum aestivum) studied (Franchini et al., 2004). Cover crops may play a role in integrated pest management (IPM) practices by either altering the life cycle of the insect pest or by producing some inhibitory substances. Velvetbean [Mucuna deeringiana (Bort) Merr] has a strong inhibitory effect on the gall index of M. incognita in the roots of tomato (Caamal-Maldonado et al., 2001). Various cover crops are used to suppress weeds in different parts of the world. The canopy cover produced by the cover crops is important in controlling weeds by photosynthetic suppression. Apart from the cover crop biomass, there are some other factors that are 7 helpful in suppressing weeds effectively, including the quickness in establishment of the cover crop (Barberi and Mazzoncini, 2001) and the ability to demobilize available nutrients from the field in fallow. Fibrous rooted cereal cover crops can scavenge the excess nutrients present in the soil after the harvest of the cash crop and make them available later; thus, this may decrease the weed population. The leguminous cover crops release symbiotic nitrogen to the soil, which decreases the effectiveness of them in suppressing the weeds population. Also, allelopathic chemicals released by the active crop or cover crop residues are important in weed suppression. A cover crop management system has a clear advantage in weed control compared to the winter fallow system (Reeves et al., 2005). Velvetbean [Mucuna deeringiana (Bort)Merr] is used in tropical regions of Mexico to suppress spiny amaranth (Amaranthus spinosus L.), smooth pigweed (A. hybridus L.), field sandbur (Cenchrus insertus M. A. (Curtis), and bitterweed (Parthenium hysterophorus L.) (Caamal- Maldonado et al., 2001). In a field trial conducted in the northern Guinea savanna of Nigeria, it was shown that velvetbean combined with 40,000 corn plants ha-1, and weeding three times gave higher corn grain yields and efficient weed control than a farmer's control consisting of a single weeding at 4 weeks after planting (WAP) and low corn density. (Chikoye et al., 2004). Even though cover crops can be used to suppress weeds, even cover crops may be considered weedy in certain situations. The botanical characteristics that predispose a cover crop to become a potential weed are: 1) the ability of the plants to produce seeds at an early stage of its life cycle and continue seed production till the end of its life cycle, 2) the easy shattering of seeds, 3) production of a large number of seeds, 4) high seed dormancy even after long exposure to 8 harsh environmental conditions or no dormancy at all, 5) quick germination and establishment, and 6) the ability to propagate vegetatively. The non-shattering nature of seeds in black oat compared to its wild relatives and the low survival of volunteer seeds in harsh environmental conditions during the summer, where high moisture and high temperature lead to a rapid degradation of seeds without a hard seed coat, reduces the potential threat of black oat as a weed in actual field conditions in southeastern USA. Allelopathy The allelopathic effect of a cover crop may negatively affect the crop growth in some cases. The allelopathic effects of some plant residues on the yield parameters of other crops might be reduced by proper tillage and other practices that promote rapid decomposition of the plant materials (Roth et al., 2000). On the other hand it is an efficient method for controlling the weed without chemical application. The allelopathic potential of a cover crop can be estimated by growing the plants in greenhouse conditions and conducting in-vitro germination and radicle growth bio-assays using aqueous leachates collected from them at a standard concentration (1%) (Caamal-Maldonado et al., 2001). In velvet bean L-3-(3,4-dihydroxyphenyl) alanine (L-DOPA) is mainly responsible for the allelopathic action (Nishihara et al., 2005). The use of genetic engineering to impart allelopathic potential to cover crops has been a discussion among scientists. Many, however, are skeptical about the effectiveness of such a strategy (Duke et al., 2001). Farmers in Mexico use leguminous species like Mucuna spp. and Canavalia spp. to control weeds in their fields (Caamal-Maldonado et al., 2001). 9 BLACK OAT Biomass Production Recently black oat (A. strigosa Schreb.) has become very important in subtropical and temperate regions as a winter cover crop and forage (Suttie, 2004). In South America black oat is grown on more than 3 million hectares as a cover crop or forage (Federizzi and Mundstock, 2004). It has the potential to produce a considerable amount of biomass in comparison with other non-leguminous or leguminous cover crops. In addition to that, it has many desirable qualities over the other cover crops. In a study conducted by Schomberg et al. (2005) results showed that the biomass production and soil N mineralization dynamics of black oat was similar to crimson clover, indicating the potential of black oat as a cover crop in the southeast USA. The amount of N mineralized in 90 days (Nmin90) measured with in situ soil cores was 1.3 to 2.2 times greater following black oat, crimson clover, and oilseed radish than following rye (Schomberg et al., 2005). Black oat can be used as a forage crop and produce a comparable dry matter yield to that of ryegrass (Lolium perenne L. cv. Kangaroo Valley) and it can also thrive well with other legume forage crops like barrel medic (Medicago truncatula L.) (Lowe and Bowdler, 1998). A study conducted at Instituto Agron?mico do Paran? IAPAR, Brazil demonstrated the ability of cover crop residues of black oat to decrease manganese toxicity in well-aerated, acid soils by lowering the Mn solubility (Andrade et al., 2002). Another advantage of black oat is the relative ease of field establishment. Black oat only needs N as a top dressing; neither P nor K is needed (Federizzi and Mundstock, 2004). In South America, black oat cultivated for cover crop purpose is desiccated in August 10 (Federizzi and Mundstock, 2004). Black oat reached maximum biomass at anthesis (8579 kg ha -1), while rye (Secale cereale L.) and wheat (Triticum aestivum L.) continued to increase biomass significantly through soft dough (9497 kg ha -1 and 10460 kg ha -1, respectively) (Ashford and Reeves, 2003). Therefore, black oat can be terminated at an earlier stage compared to the other two cover crops. Early termination will reduce depletion of the available nutrients and moisture in the field. This is a useful trait since it can be planted as a fall-sown winter cover crop. If the winter is severe it will all be killed so there is no need for the use of herbicides to kill the cover crop. Since black oat has the C3 photosynthetic pathway for Carbon fixation (Tesar, 1984), it can contain more available NH4+ per dry matter mass unit compared to C4 cover crops such as Pennisetum glaucum (Waller, 1979), Sorghum vulgare (Waller, 1979), and Brachiaria decumbens (Rosolem CA, 2005). Cotton lint yield following black oat was higher than that following rye, even though rye produces more biomass than black oat (Bauer and Reeves, 1999). Even though black oat can thrive well with other cover crops in mixed culture with wheat black oat performs poorer than in monoculture in terms of biomass production (Cousens et al., 2003). Weed Control Black oat can suppress the weeds cutleaf evening primrose (Oenothera laciniata Hill) and common chickweed (Stellaria media (L) Vill) (Reeves et al., 2005). In years without any freezing injury, black oat provides better weed control than rye (Reeves et al., 2005). Black oat has a greater inhibitory effect on root elongation of radish than rye suggesting the suitability of black oat as mulch for weed control (Bauer, 1999). Black oat 11 can perform well even in mixtures with other cover crops. Saini et al., (2005) reported a 40% winter weed biomass reduction by mixed covers of lupin (80%) and black oat (20%) preceding corn, but these mixed covers were less effective preceding cotton. Weed biomass produced is less in cotton planted in black oat or rye covers compared to that planted in wheat or fallow covers. Without herbicides, black oat gave greater sickle pod [Senna obtusifolia (L.) H. S. Irwin & Barnaby] and palmer amaranth control than rye or wheat, showing the suitability of black oat as an effective cover crop for weed suppression (Patterson et al., 1996). Management Practices Black oat has a low C/ N ratio of 34:1 compared to 42:1 for oat and wheat and 45:1 for rye (Bauer and Reeves, 1999). This is desirable for the main crop in regions with high rainfall and temperatures during the growing season because the decomposition of the cover crop residue is slowed down. However, it may also sequester the nitrogen available to the main crop and, hence, application of starter N to the main crop may be warranted (Ceretta et al., 2002). Obviously, the kill date has an effect on biomass yield and available nitrogen and maximizing the days between cover crop establishment and kill is a desirable practice. A delayed kill date of hairy vetch for two weeks can improve N accumulation significantly (from 104 to 113 kg ha-1) (Sainju and Singh, 2001). Using chemicals to kill the cover crop may be advantageous for the following main crop (Vyn et al., 2000). The most effective and economical method to kill black oat at anthesis is the combination of roller and herbicide (88% with roller+paraquat and 91% with roller+glyphosate) (Ashford and Reeves, 2003). The use of a roller also facilitates 12 planting by reducing hairpinning of residue when the planter runs parallel to the roller (Ashford and Reeves, 2003). There may be a difference in the response of cover crop performance based on the planting date (Bauer and Reeves, 1999). Black oat had higher N concentration than other winter cereals (oat, rye and wheat) for October and November planting dates (Bauer and Reeves, 1999). The date of planting affects the cover crop dry matter yield, N content and C/N ratio (Odhiambo and Bomke, 2001). In a study conducted in Britain, cover crops performed better in terms of dry matter yield and N accumulation if planted in late August compared with late September (Odhiambo and Bomke, 2001). However, the planting date of the cover crop had no influence on cotton lint yield in the southeastern United States (Bauer and Reeves, 1999). Considering all these aspects, black oat, which is widely grown in Brazil and Paraguay as a cover crop, can be used as a winter cover crop in the cotton belt of southeastern USA due to the climatic similarity between these places (Bauer and Reeves, 1999). Classification and Botany Black oat (Avena strigosa Schreb.) is a member of genus Avena of the Aveneae tribe within the Pooideae subfamily of the grass family Poaceae. The Latin binomial is particularly useful in communication because (i) the common name black oat is also sometimes applied to other oat species and (ii) in the English speaking regions of the world Avena strigosa Schreb. is referred to by different common names such as bristle oat, sand oat, or small oat. Common names for A. strigosa in other languages are avoine 13 rude in French, Rauhhafer and Schwarzhafer in German, and aveia-preta in Portuguese (USDA GRIN Taxonomy 1997). Avena strigosa can be confused with two closely related diploid species viz. Avena hispanica and Avena brevis. The conclusive identification can be made with the inspection of the unique strigosa-type lodicules in which the side lobe is larger than that of sativa and fatua type lodicules and is fused partly or almost completely to the conical part of the lodicules above the level of troughing, sometimes near the very tip of the lodicules (Baum, 1977). Black oat is an annual (Baum, 1977; Legget, 1992) and juvenile growth and flowering stems are either prostrate or erect. The height of flowering stems ranges from 80 to 200 cm. (Legget, 1992). Ligules are obtuse and sometimes pointed (Baum, 1977). Panicles are equilateral and spikelets are short measuring 20 to25 mm long without the awns, each of which consists of two to three florets. The glumes are equal or nearly equal in length (the length may range from 16 to 24 mm) and are non-disarticulating at maturity. Awns inserted at the middle of the lemma and tips of lemmas are bisetulate- biaristulate or sometimes biaristulate only. Lemmas are glabrous or not and sometimes they bear only a few hairs around the point of awn insertion. The palea has 1-2 rows of cilia along the edge of the keel and the back of the palea is often beset with prickles, rarely without. The lodicules are with prickles (Baum, 1977). There is not much information available about the phenological changes other than a brief account given by Baum (1977) regarding the flowering of black oat from June to September and rarely in October. 14 From very early times black oat has been cultivated for different purposes in different parts of the world. Prior to the 17th century Avena strigosa was the most common oat cultivated in Scotland (Murphy and Hoeffman, 1992). Black oat is used as an animal forage, green manure and cover crop and in erosion control (Anonymous). In Brazil much of the fodder oat is Avena strigosa rather than Avena sativa. (Martinelli, 2004). In Japan Avena sativa and Avena strigosa are the cultivated fodder oats (Katsura, 2004). Avena strigosa Schreb, which formerly was a minor cereal of poor soils, is now grown on a large scale in southern Brazil, Chile, Uruguay and Paraguay (Anonymous, 2004). In southern Brazil, Black oat is cultivated as winter forage, cover crop and for grain production. (Ceretta et al., 2002). Center(s) of diversity Coffman (1961) citing Sampson (1954) who in turn cited Tackholm et al. (1941) stated that ?What are probably the oldest known oat grains were found in Egypt associated with the remains belonging to the 12th dynasty [2000 to 1788 BC]. Similar grains have been found among Egyptian cereals of the 2nd and 3rd century AD. These Egyptian oats were originally identified as Avena strigosa, but Tackholm et al. believe they are either A. fatua or A. sterilis.? Avena strigosa is distributed in Austria, Belgium, Corsica, Czech Republic, Slovakia, Denmark, Finland, France, Germany, Hungary, Lithuania, Luxemburg, Norway, Portugal, Spain, Sweden, Switzerland, the United Kingdom, and USSR (Baum, 1977). Presently it is grown commercially in South America as a cover crop or for grain to be sown as cover crop (Federizzi and Mundstock, 2004) and to a limited extend in 15 North America also. Even though black oat was introduced to the United States from Europe, it has become naturalized in California (Magness et al., 1971).The strigosa group is seen in vast areas from the Iberian Peninsula, considered to be the center of origin, to the plains of Afghanistan occupying a wide range of ecological niches (Weibull et al., 2005). Black oat is cultivated in France, Belgium, Portugal, Spain, northwest Germany, and Great Britain (Coffman, 1961). Black oat is cultivated in Wales to a limited extent on poor upland soils and to a greater extent in Germany, the United Kingdom, and various parts of Eastern Europe (Baum, 1977). In Latin America the cultivated black oats are introductions from Europe (Federizzi and Mundstock, 2004). A more detailed account of the present geographical distribution of black oat is found in the Flora Europeae (Anonymous). In many of these regions different cultivars have been developed as a result of cultivation or naturalization. The main black oat cultivars used in Peru are Vilcanota, Mantaro and Pastos (Federizzi and Mundstock, 2004). The United States Department of Agriculture National Germplasm Resources Information Network (USDA-GRIN) lists 121 accessions stored at the National Small Grains Collection (NSGC), Aberdeen, Idaho, of which 119 are available to researchers around the world (http://www.ars-grin.gov/cgi- bin/npgs/html/tax_acc.pl, verified on June 18, 2007). Cytogenetics Like the genus Triticum, species in the genus Avena constitute a polyploid series with a basic chromosome number of x = 7. There are 23 species belonging to the three genome groups with three ploidy levels. All diploid species contain either the A or C 16 genome, the tetraploid species contain the A and C genomes, and the hexaploids have the ACD genomic constitution. Thus, the A and C genomes occur at diploid, tetraploid and hexaploid levels, but the D genome is present at the hexaploid only (Leggett and Markhand, 1995). Avena strigosa is a diploid species with the A genome and a chromosome number of 2n = 2x = 14 (Baum, 1977; O'Mara, 1961; Thomas, 1992), Avena strigosa weistii is another diploid with As genome. A. ventricosa Bal. ex. Coss is a diploid with CvCv and both A.caudate Dur. and A.eriantha Dur. are diploids with the CpCp genome. A.barbarate Pott ex Link., A.abyssinica Hochst and A.vavilovania(Malz.) Mordv. are tetraploids with AABB genomes and A.murphyi Ladiz. and A.maroccana Gdgr. are tetraploids with AACC genomes. There are six hexaploid species identified with AACCDD genome viz. A.sativa L., A.byzantina C.Koch., A.sterilis L., A. fatua L., A. hybrida Petern., A.atherantha Presl., A.occidentalis Dur., and A. trichophylla C.Koch. (Thomas, 1992). The C genome is quite different from both the A and D genomes. Based on the Giemsa C-banding technique, it can be seen that the heterochromatin in genome A is located at the telomeres, whereas it is located at the centromeric and interstitial regions in the C genome and is spread throughout the chromosome in the D genome (Linares et al., 1992). The species with A genome have symmetrical chromosomes with low heterochromatin content, whereas those with C genome have asymmetrical heterochromatic chromosomes (Fominaya et al., 1988). Failed attempts to distinguish between the A and D genomes may be an indication of the possible role of A genome as a donor of both A and D genomes of the hexaploid oat. In order to find the role of diploid oat species in the evolution of the hexaploid species, a clear understanding of evolution 17 of various genomes and intergenomic translocations is considered to be significant (Linares et al., 1998). The cytogenetic map which is a visual representation of chromosomes when stained and examined under a microscope provides valuable information in cytogenetic studies. With the advancement of technology, a high resolution cytogenetic map obtained from Fluorescence in situ Hybridization (FISH) has provided important biological information on genome organization and functions. FISH is a molecular cytogenetic technique that can be used to identify and localize the presence or absence of specific DNA sequences on chromosomes. It uses fluorescent probes of desired length and sequence, which hybridize only to the complementary sequences in the chromosomes. The probe is actually a single stranded denatured DNA mixed with a fluorescent dye and it is mixed with the denatured target DNA (combed DNA) for hybridization. The specific tagged sequence can then be visualized using a fluorescence microscope. On the other hand GISH (Genomic in situ hybridization) is another molecular cytogenetic technique used to find a genomic relationship among different species or genus. Using this technique chromosomes or genomes from different parents or ancestors can be identified by means of differential hybridization of entire genomic probes. The highly irregular chromosome pairing in a cross between A. macroccana (AACC) and the autotetraploid plant produced by A. strigosa Schreb.(AsAs) and A. eriantha Dur.( CpCp) (Legget, 1998) discards the chance that A. strigosa and A. eriantha participated in the formation of the tetraploid A. macroccana (AACC) (Legget, 1998). The low chromosome pairing in a hybrid between A. strigosa and A. insularis excludes A. strigosa as a diploid progenitor of A. insularis (Ladizinsky, 1999). A cross between 18 tetraploid A. abyssinica and A. strigosa can form a triploid (Dilkova et al., 2000b). The genome of Avena longiglumis is different from the A genome of all other Avena species and it is designated as Al. The total length of the chromosomes of Avena strigosa Schreb. is 17 units shorter than that of Avena longiglumis, which is equal to the longest arm in the strigosa set. This indicates a substantial loss of chromatin material from the strigosa group. This may be due to the elimination of acentric fragments due to translocations in the strigosa genome rather than a chromatin gain due to duplication in the Avena longiglumis genome. The F1 produced from crosses between Avena longiglumis, Avena strigosa and Avena hirtula are sterile due to chromosome incompatibility among themselves. (Rajhathy, 1961). Avena insularis Ladizinsky was found to be the tetraploid progenitor of the regular oat Avena sativa after studying the F1 between these two species. It contains two pairs of satellite chromosomes and one pair of subterminal chromosome more morphologically similar to Avena magna than any other tetraploids. However, in A. magna three pairs of satellite chromosomes are present. Avena insularis Ladizinsky forms pentaploid hybrids with Avena sativa but seed set happens only if the Avena sativa is used as the female parent; meiosis is irregular in these hybrids. The mean number of chiasmata per cell in the hybrid formed from a cross between Avena sativa and Avena insularis is higher (88%) than the mean number of chiasmata in hybrids formed from crosses involving Avena sativa with other tetraploids such as Avena magna (75%), Avena murphyi (62%) and Avena barbata (42%). This suggested a closer resemblance of Avena insularis to Avena sativa than any other oat species (Ladizinsky, 1998). 19 Zhou et al. (1999) suggested Avena sterilis L. as the putative progenitor of the cultivated hexaploid oat Avena sativa L. and Avena byzantina C. Koch. based on the cluster analysis of 248 polymorphic RAPD (Random Amplified Polymorphic DNA) markers and the studies of 7C-17 intergenomic chromosomal translocation among the accessions of these three species. They also proposed a dichotomy or divergence in speciation during the period of domestication that leads to the formation of both Avena sativa L. and Avena sterilis L. Avena barbarata was introduced to California from Spain during the seventeenth and eighteenth centuries. The gene pool present in California is similar to the present day Spanish gene pool based on allelic and single-locus genotype composition, but different on a multilocus genotype basis. (Garcia et al., 1989). Avena agardiriana Baum et. Fedak is a recently discovered tetraploid (2n= 4x = 28). Its C-banding pattern revealed that it shows resemblance to A/B/D genomic groups of chromosomes of Avena species rather than the C genomic group (Jellen and Gill, 1996). Avena strigosa, Avena wiestii and Avena hirtula are karyotypically similar with two metacentric, two submetacentric, one subacrocentric, and two morphologically different satellite (SAT) chromosomes (Badaeva et al., 2005). Pairing inhibitor genes In allopolyploids such as wheat (Triticum aestivum) diploid-like pairing occurs during meiotic division. This means that homologous chromosomes pair as bivalents rather than homoeologous chromosomes pairing as multivalent. Homoeologous are partially homologous chromosomes originating from different ancestral genomic groups. 20 This mechanism is governed by the gene Ph1, which is a trans-acting gene affecting centromere-microtubules interaction (Vega and Feldman, 1998). This kind of genetic control of meiotic pairing is observed in other allopolyploids as well, e.g., Avena sativa L. and Festuca arundinacea (tall fescue) (Jenczewski and Alix, 2004). In wheat another gene (Ph2) controlling the pairing of homoeologous chromosomes is present on chromosome 3D, but it is a rather weaker suppresser than Ph1 (Mello-Sampayo, 1971). Hexaploid oat has three genomes that might have derived from different ancestral genomes (or three sets of seven chromosome pairs). Each chromosome is capable of pairing with five other related chromosomes, one homologue and four homoeologous, during meiosis, but actually pairs only with the homologous chromosome. This pairing behavior is controlled by pairing control genes (PCG). It is hypothesized that the grass genome might have originated from an ancestor with holocentric chromosomes. Holocentric chromosomes have diffuse centromeres and possess multiple cites for microtubule attachment (Moore, 1998). Newly formed allopolyploids may display homoeologous pairing with multivalent formation resulting in reduced fertility, but as generations advance, the formation of multivalent decreases sharply due to natural selection of plants having more pairing control genes (Jenczewski and Alix, 2004). Avena barbata Pott ex Link formed from the polyploidization of Avena hirtula Lag. and Avena wiestii Steud. complex showing bivalent pairing during meiosis. This shows that the homeologous pairing is suppressed in this tetraploid (Allard et al., 1993). Thomas and Rajhathy (1966) observed that initial pairing of chromosomes in an F2 population of a cross between Avena abyssinica Hochst. and Avena barbarata took place at early prophase, but desynapsis occurred and was associated with a high incidence of univalents 21 at Metaphase I. They suggested the role of a single recessive gene ds2 for this pairing control. Molecular Markers Even though different plant species are morphologically different, they might have arisen from a common ancestor during the course of evolution. The ubiquitous grass family (Poaceae) is one of the most studied plant groups at all aspects from morphological to molecular level. This family is further divided into six or seven subfamilies with about 40 tribes and 600 to 700 genera (Mathews et al., 2000). In order to classify the vast number of grasses, earlier scientists employed the classical approach of studying the morphology of flowering parts and the plant as a whole. Most of the recent studies on grass phylogeny are based on data from chloroplast genomes and a few from the information based on the data from nuclear genomes. The phylogenetic analysis of data obtained from the partial phytochrome B nuclear DNA sequences (nuclear PHYB) is a modern technique in phylogenetic studies (Mathews et al., 2000). The genome co-linearity or synteny among different species is the basis of comparative mapping. Closely related species show convergence in genome structure, whereas distant ones show greater divergence. In a study conducted at Cornell University comparing the oat genome with Triticeae species, rice and maize genomes revealed the conservation of certain regions of homologous segments among these groups (Deynze et al., 1995). The integrated grass genome map consists of species of six different tribes and three different subfamilies: viz. Bambusoideae (rice etc), Pooideae (oats and Triticeae) and Panicoideae (Devos and Gale, 1997). In an oat linkage group 134 DNA sequences 22 were assigned to 10 chromosomes associated with the syntenic group using nullisomics of hexaploid oats (Kianian et al., 1997). A genetic linkage map is a useful tool for the localization of qualitative and quantitative traits loci for marker assisted selection and breeding for agronomically important traits. Even though different linkage groups are present in oat species, the correspondence of individual A. strigosa chromosomes to these linkage groups or loci is still unknown. Genetic linkage can be explained as the association of genes located on the same chromosomes. In a linkage map, map distance is a statistical estimate of the crossover and physical distance is the number of DNA pairs between two linked genes. Aneuploids are used for linkage mapping because of the ease of assigning the gene families, monomorphic Restriction fragment length polymorphism (RFLP) sequences, and oat linkage groups to chromosomes. Aneuploids can be produced by various techniques such as X-ray irradiation at doses varying from 75r to 600r (Andrews and McGinnis, 1964). The direct approach for assigning linkage groups to individual chromosomes would be to hybridize genetically mapped RFLP probes to chromosomes. An alternative approach is to directly amplify sequence-tagged site (STS) markers, derived from genetically mapped RFLP clones in the DNA of microdissected chromosomes. Based on the two or four RFLP-derived STS markers, A. strigosa chromosomes 2 and 3 were found to be homologous to the oat linkage groups C and E, respectively. Chromosome 7 corresponds to linkage group F and was most probably involved in an A. strigosa-specific chromosomal translocation relative to the diploid species A. atlantica and A. hirtula (Loarce et al., 2002). Based on Amplified fragment length polymorphism (AFLP) and 23 RAPD dendrograms, A. prostrata and A. longiglumis have the most divergent A genomes and are considered to be the most ancient, while the As ( A. strigosa) genome is the most recently evolved (Drossou, 2004). Zhu and Kaeppler (2003) compared the hexaploid oat linkage map produced from a mapping population of a recombinant inbred line derived from the F5:6 lines of a cross ?Ogle/MAM17-5? (OM) to the previous linkage map produced from a mapping population of ?Kanota/Oagle? (Wight et al., 2003). They identified three putative homoeologous groups 5 cM or longer out of the 28 linkage group determined. Group one includes OM7, OM8 and OM18, group two includes OM2 and OM23, and group 3 includes OM13 and OM16. Nine linkage groups identified were homologous to the linkage groups in the KO map. The relevance of the MO mapping population is that it is segregating for a number of agronomically important traits (Zhu and Kaeppler, 2003). Breeding Programs Even though black oat has these promising features as a cover crop it has some drawbacks that need to be corrected by the implementation of a proper breeding program. Biomass production of black oat is reduced compared to rye if low night temperature persist for long periods of time (Reeves et al., 2005). This is due to freezing injury. Even though there are six oat-breeding programs active in South America there is no true breeding program in Brazil for A. strigosa (Federizzi, 2004). Cold hardiness of black oat needs to be improved through breeding or selection (Schomberg et al., 1995; Bauer 1999). Black oat (A. strigosa cv. Saia) was found to be susceptible to root knot nematode (Meloidogyne marylandi, M. javanica and M. incognita in a study in Israel), while A. 24 sativa was resistant or a non-host (Oka et al., 2003). This indicates that we need to concentrate on this aspect also in a breeding program. However another study conducted in Brazil, using five cultivars of black oat demonstrated that all of them are resistant to Meloidogyne incognita and M. paranaensis. (Moritz et al., 2003). In southeastern USA nowadays reniform nematode (Rotylenchulus reniformis Linford & Oliveira) is more problematic than Meloidogyne. A. strigosa has been used in many oat breeding programs to impart disease resistance to cultivated oats as it is an important source of resistance to crown rust (Puccinia coronata f. sp. A.e) (Weibull et al., 2005). The crown rust resistance gene is a complex with 9 genes involved (Dilkova et al., 2000; Rayapati et al., 1994). The stem rust (caused by Puccinia graminis Pers f.sp avenae Erikss. and Henn) resistance gene is also present in Avena strigosa strains C.D. 3820 and C.I. 3078. The gene is a single dominant gene (Dyck, 1966). However the hybridization incompatibility of the diploid black oat with the natural hexaploid has been a problem. Successful hybridization between A. strigosa cv. Saia (2n = 14) and A. magna (2n = 28) and the induction of a hexaploid form using colchicine treatment of the triploid hybrid were reported when A. strigosa was used as the female parent. However, this hexaploid failed to retain its barley yellow dwarf virus (BYDV) resistance even though it retained its crown rust resistance (Ladizinsky, 2000). For transferring the desirable traits from a diploid to a hexaploid species, the first step is a cross between diploid Avena strigosa and a tetraploid such as Avena abyssinica to form a triploid. Then, the 6x amphiploid is induced by colchicine treatment of the triploid and it will be hybridized with the hexaploid oat to transfer the desired characteristics. C- banded karyotyping can be used to verify the substitution of 25 the desired gene (Dilkova et al., 2000). According to Forsberg ?several barriers to inter- specific gene transfer must be overcome to transfer genes for resistance from diploid species such as A. strigosa to A. sativa? (Forsberg and Shands, 1969). Based on the preceding literature review it is clear that cover crops are important for conservation practices and that black oat is a suitable cover crop for the Southeastern USA. The only commercially available black oat cultivar in United States is SoilSaver, released in 2002 by USDA-ARS and The Alabama Agricultural Experiment Station. Even though SoilSaver is superior in many traits like maturity and biomass yield than many other accessions, some traits need to be improved. In order to start a breeding program the foremost important thing needed to be done is the evaluation of available germplasm, since without genetic variation selection for superior characters can not be made. There are 120 accessions of black oat accessions available from ?USDA-ARS Small Grains Germplasm Unit? at Aberdeen, Idaho, but a detailed study of this germplasm collection for maturity and morphology needs to be done before starting a breeding program. The objective of my research is the characterization of the entire USDA-GRIN Avena strigosa Schreb. germplasm collection based on reproductive maturity and morphological traits. 26 References Allard, R. W., P. Garcia, L. E. Saenz-de-Miera, and M. P. de-la-Vega. 1993. Evolution of multilocus genetic structure in Avena hirtula and Avena barbata. Genetics 135:1125-1139. Andrade, E., M. Miyazawa, M. A. Pavan, and E. L.de-Oliveira. 2002. Effect of organic matter on manganese solubility. 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Cytogenetics-The fatuoid and steriloid mutations, p. 112-124, In F. A.Coffman, ed. Oats and Oat improvement. Agron. Monogr. 8. ASA, Madison, WI. Odhiambo, J. J. O., and A. A. Bomke. 2001. Grass and Legume Cover Crop Effects on Dry Matter and Nitrogen Accumulation. Agron. J. 93:299-307. Ohm, H. W., and G. Shaner. 1992. Breeding Oat for Resistance to Diseases. Oat science and technology-Agronomy Monograph 33:657-698. Oka, Y., G. Karssen, and M. Mordechai. 2003. Identification, host range and infection process of Meloidogyne marylandi from turf grass in Israel. Nematology 5(5): 727-734. Patterson, M. G., D. W. Reeves, and B. E. Gamble. 1996. Weed management with black oat (Avena strigosa) in no-till cotton, p. 1557-1558 IN Beltwide Cotton Conf.,January 8-12, 1996 Nashville, TN. National Cotton Council. Price, A. J., D. W. Reeves, and M. G. Patterson. 2006. Evaluation of weed control provided by three winter cereals in conservation-tillage soybean. Renewable Agriculture and Food Systems 21(3):159-164(6). Rajhathy, T. 1961. Chromosomal differentiation and speciation in diploid Avena. Can. J. Genet. Cytol. 3:372-377. Rayapati, P. J., J. W. Gregory, M. Lee, and R. P. Wise. 1994. A linkage map of diploid Avena based on RFLP loci and a locus conferring resistance to nine isolates of Puccinia coronata var. avenae. Theoretical and Applied Genetics 89:831-837. 34 Reeves, D. W., A. J. Price, and M. G. Patterson. 2005. Evaluation of three winter cereals for weed control in conservation-tillage nontransgenic cotton. Weed Technology 19:731-736. Rosolem CA, C. J., Foloni JSS. 2005. Leaching of nitrate and ammonium from cover crop straws as affected by rainfall. Communications in Soil Science and Plant Analysis 36 (7-8):819-831. Roth, C. M., J. P. Shroyer, and G. M. Paulsen. 2000. Allelopathy of Sorghum on Wheat under Several Tillage Systems. Agron. J. 92:855-860. Saini, M., A. J. Price, and E. Van Santen. 2005. Winter Weed Suppression By Winter Cover Crops In A Conservation-Tillage Corn And Cotton Rotation, p. 124-128. In proceedins of the southern conservation tillage systems conferencec, Vol. June 27-29, 2005, Florence, South Carolina. Sainju, U. M., and B. P. Singh. 2001. Tillage, Cover Crop, and Kill-Planting Date Effects on Corn Yield and Soil Nitrogen. Agron. J. 93:878-886. Sainju, U. M., B. P. Singh, and W. F. Whitehead. 1998. Cover Crop Root Distribution and Its Effects on Soil Nitrogen Cycling. Agron. J. 90:511?518. Schomberg, H. H., D. M. Endale, A. Calegari, R. Peixoto, M. Miyazawa, and M. L. Cabrera. 2005. Influence of cover crops on potential nitrogen availability to succeeding crops in a Southern Piedmont soil. Biology and Fertility of Soils 42:299-307. Sharpley, A. N., R. W. McDowell, and P. J. A. Kleinman. 2001. Phosphorus loss from land to water: integrating agricultural and environmental management. Plant and Soil 237:287-307. 35 Silburn, D. M., B. W. Simpson, and P. A. Hargreaves. 2002. Management practices for control of runoff losses from cotton furrows under storm rainfall. II. Transport of pesticides in runoff. Aust. J. Soil Res. 40:21-44. Staver, K., and R. Brinsfield. 1998. Using cereal grain winter cover crops to reduce groundwater nitrate contamination in the mid-Atlantic coastal plain. J. Soil Water Conserv. 53(3):230-240. Terra, J. A., J. N. Shaw, D. W. Reeves, R. L. Raper, E. van Santen, E. B. Schwab, et al. 2005. Soil Management and Landscape Variability Affects Field-Scale Cotton Productivity. Soil Sci. Soc.Am.J. 70:98-107. Tesar, M. B. 1984. Physiological basis of crop growth and development. American Society of Agronomy Crop Science Society of America, Foundations for modern crop science series. 13:341. Thomas, H. 1992. Cytogenetics of Avena, p. 473-507, In H.G.Marshall and M.E.Sorrells, eds. Oat Science and Technology-Agronomy monograph, Vol. 33. American Society of Agronomy, Madison, WI, U.S.A. Thomas, H., and T. Rajhathy. 1966. A gene for desynapsis and aneuploidy in tetraploid Avena. Can. J. Genet. Cytol. 8:506-515. Van Deynze, A. E., J. C. Nelson, L. S. O'Donoughue, S. N. Ahn, W. Siripoonwiwat, S. E. Harrington, et al. 1995. Comparative mapping in grasses. Oat relationships. Mol Gen Genet 249(3):349-356. Vega, J. M., and M. Feldman. 1998. Effect of the Pairing Gene Ph1 on Centromere Misdivision in Common Wheat. Genetics 148:1285-1294. 36 Weibull, J., L. Lyng, J. Bojensen, and V. Rasomavicius. 2005. Avena strigosa in Denmark and Lithuania: Prospects for in situ conservation. Plant Genetic Resources Newsletter 131:1 - 6. Weinert, T. L., W. L.Pan, M. R. Moneymaker, G. S.Santo, and R. G.Stevens. 2002. Nitrogen recycling by nonleguminous winter cover crops to reduced leaching in potato rotations. Agron. J. 943:365-372. Wight, C. P., N. A. Tinker, S. F. Kianian, M. E. Sorrells, L. S. O?Donoughue, D. L. Hoffman, et al. 2003. A molecular marker map in ?Kanota? ? ?Ogle? hexaploid oat (Avena spp.) enhanced by additional markers and a robust framework. Genome 46:28-47. Zhou, X., E. N. Jellen, and J. P. Murphy. 1999. Progenitor Germplasm of Domesticated Hexaploid Oat. Crop Sci. 39:1208-1214. 37 II. MORPHOLOGY AND MATURITY OF BLACK OAT (AVENA STRIGOSA SCHREB.) Abstract Black oat (Avena strigosa Schreb.) is a potential cover crop for the southeastern United States. We evaluated the entire USDA-ARS Germplasm collection for identifying the accessions suitable for cover crop purpose in southeastern US conditions. One hundred four accessions were planted at Shorter, Alabama on a Norfolk sandy loam (coarse-loamy, siliceous, subactive, thermic, Plinthic, Paleudults) during 2003-04 and 2004-05. Agronomic traits and maturity were studied. Relevant traits that can differentiate the accessions identified after the forward stepwise selection procedure (STEPDISC) were used for canonical discriminant analysis (CDA). The first four canonical discriminate variates (CAN) had Eigenvalues ? 1 and are responsible for 84 % of the total variation among the entire population for both years. Plotting CAN1 vs. CAN2 differentiated Accession CIav 9015 from all other accessions in this analysis. We speculate that accession CIav 9015 may not be Avena strigosa Schreb., the species under consideration, but some other species of Avena. Cytogenetic and molecular marker study may be needed for a conclusive identification of this accession. CDA also separated four 38 accessions from Europe and one from Australia to the extreme right of the first quadrant with high positive values for both CAN1 and CAN2 variates. The accessions studied are significantly different based on individual traits among and within countries and continents. South American accessions are with prostrate habit and are suitable for cover crop purpose in the southeastern US. Accessions from Europe and Australia are late maturing and may not be suitable for the southeastern US condition, but may be suitable for the colder parts where winter kill is employed for the termination of the cover crop. Introduction Black oat (Avena strigosa Schreb.) is a diploid species with As As genome and a chromosome number of 2n = 2x = 14 (Baum, 1977; O'Mara, 1961; Thomas, 1992). Originating in the northern parts of Spain and Portugal (Weibull et al., 2005), black oat has spread to different parts of the globe (Fig. 2-1.) (Baum, 1977; Coffman, 1977; Federizzi and Mundstock, 2004; Weibull et al., 2005). Even though different in ploidy, diploid black oat has been used in many hexaploid common oat (A. sativa L.) breeding programs as a donor parent for some desirable characters such as crown rust (Dilkova et al., 2000) and stem rust resistance (Dyck, 1966). Black oat has become an important winter cover crop in subtropical and temperate regions (Suttie and Reynolds, 2004) and is cultivated on more than 3 million hectares in South America (Federizzi and Mundstock, 2004), especially in southern Brazil (Ceretta et al., 2002). Experiments conducted in the southeastern United States revealed its potential to become a major cover crop in that region (Bauer and Reeves, 1999). Black oat has biomass production and nitrogen dynamics comparable to crimson clover (Schomberg et 39 al., 2005). It also has the potential to be grown as a forage and fodder crop and can thrive well with leguminous forage crops (Katsura, 2004; Lowe and Bowdler, 1998; Martinelli, 2004). Cotton lint yield following black oat was higher than that following rye. Black oat has a low C/ N ratio of 34:1 compared to 42:1 for common oat and wheat and 45:1 for rye (Bauer and Reeves, 1999). Thus the availability of nutrients through degradation of plant residues when used as a cover crop will be faster in black oat than other small grain cover crops. Studies in Brazil revealed black oats also has the potential to decrease manganese toxicity in well aerated acidic soils (Andrade et al., 2002). The only commercially available black oat cultivar in the United States is ?SoilSaver?, which was released by Auburn University and USDA in 2002. Even though SoilSaver is superior to other black oat accessions for some traits such as maturity and biomass yield (van Santen, unpublished data, 2005), some traits need further improvement. Over 100 black oat accessions are available from the USDA-ARS Small Grains Germplasm Unit at Aberdeen, Idaho, but a detailed study of this collection is needed before accessions can be used in a breeding program. In this paper we examine the agronomic traits of the entire USDA black oat accessions that are important for use as a cover crop and the potential of these accessions for cover crop purposes in the southeastern United States. Materials and Methods SoilSaver and 103 Avena strigosa Schreb accessions (Table 2-1) obtained from the USDA-ARS National Small Grains Collection Unit at Aberdeen, ID, USA (http://www.ars-grin.gov/cgi-bin/npgs/html/site.pl?NSGC) were used for the study. Two 40 seeds per cone-tainer (Ray Leach Cone-tainers, Washougal, WA; 2.5 cm diameter by 12 cm depth) were planted in 1:1 sand and PRO-MIX medium (Sun Gro Horticulture Distribution Inc., Bellevue, WA) at the Auburn University Plant Sciences Research Center (PSRC) greenhouse. Approximately 2 weeks after seeding, seedlings were thinned to one per cone-tainer. The seedlings were transplanted on 90 x 90 cm centers at the Field Crops Unit of the E.V. Smith Research Center, Shorter, Alabama (32?24.5'N, 85?57'W) on October 31, 2003, and November 16, 2004. The soil type of the field is a Norfolk sandy loam (coarse-loamy, siliceous, subactive, thermic, plinthic Paleudult). The experimental design was an RCBD with three replicates. Six seedlings were transplanted per year x block x entry combination. Nitrogen was applied during the 3rd week of February of each year at a rate of 36 kg ha-1. Occasional manual and mechanical weeding was done. Response variables Twelve traits were measured in this study viz. heading date, tiller angle, tiller diameter, tiller length, tiller node number, tiller number, panicle length, panicle node number, flag leaf length and width, seed yield and average seed mass (Table 2-2). Heading date was defined as the day of the year when the first tiller of a given plant had emerged 75% of its length from its leaf sheath. When all the plants in an accession were headed out, the outermost tiller from each plant was removed and observations taken for length and width of flag leaf, tiller and panicle length, tiller and panicle node number and tiller diameter. 41 The freezing temperature experienced in January 2005 killed many plants in the 2004-05 study, and this resulted in a delayed heading and harvesting dates and lower seed yield. In 2003- 2004 study plants were harvested from mid May to early June, whereas in the 2004-05 study plants were harvested from 10 to 20 June. Tiller angle was measured on one tiller per plant before harvesting using a protractor attached to a wooden ruler. Each plant was harvested separately, dried to reduce the moisture to < 10%, and stored in a paper bag until further processing. The tiller number per plant was counted and tillers were threshed using a belt thresher and cleaned with South Dakota Blower (Seedburo Equipment Co., Chicago, IL) and meshed sieves of different sizes. Total seed yield per plant was determined from cleaned seed and 1000 seed mass from a sample of 50 seeds per plant. Statistical Analysis Mixed model methodology as implemented in PROC MIXED of SAS? was used to analyze the data because of observations missing at random. Since the data are not balanced, instead of using simple arithmetic mean, there is the need to use adjusted means (least square means) for optimal representation. The method for variance component estimation is also different for unbalanced data than a balanced one where we can use ANOVA for estimating the variance of the random variable by invoking the Type3 option of PROC MIXED (http://support.sas.com/onlinedoc/913/docMainpage.jsp; verified 9th February 2007); instead in an unbalanced data we need to use ?Restricted Maximum Likelihood? (REML) method of variance estimation. The Kenward-Roger method was used for the estimation of degrees of freedom. 42 For each of the 12 response variables (Table 2-2) we calculated year x accession least squares interaction means listed in Appendix 1.Block within year was the only random effect in the model. Year, accession, and the year x accession interaction were treated as fixed effects. These interaction means were then used in discriminant analysis to investigate multivariate differences among accessions. As a first step PROC STEPDISC (SAS Institute, 1999) procedure was used for stepwise forward selection of quantitative variables discriminating among accessions. This procedure eliminated tiller number and seed yield from other response variables since they had the least canonical correlation among the 12 response variables studied. The 10 selected variables were further analyzed by canonical discriminant analysis (CDA) using PROC CANDISC (SAS Institute, 1999) with accession as class variable. Unlike fixed and pseudo-random models, where one design matrix is used for the entire model, mixed models use two design matrices say X to describe the fixed effects in the model, and Z to describe the random effects in the model. The fixed effects design matrix X has dimension n * p, where n is the number of observations in the data set and p is the number of fixed effect parameters in the model and Z has dimension n * q, where q is the number of random effect coefficients in the model. In the mixed model analysis, block nested within year was taken as the random factor and interaction means of accession x year were used for further analysis. The analyses of individual traits were based on loadings from CDA. 43 Results and Discussion The underlying assumptions of ANOVA are (1) normality of distribution of data within a group with mean ? and standard deviation ?, i.e., the data should be symmetrically distributed. A histogram is a good indicator to check this assumption; (2) homogeneity of variances, which assumes that the variances in different groups of variables are similar. The box and whisker plot can provide a visual estimation of the homogeneity of variance of observations within a group; and (3) independence of observations. The SAS? GLIMMIX procedure (http://support.sas.com/rnd/app/papers/ glimmix.pdf; verified February 7, 2007) was used to evaluate these assumptions for all response variables. For each response variable this procedure creates a graph of studentized residuals with four panels: (1) residuals vs. linear predictor, (2) histogram, (3) quantile-quantile plots, and (4) box and whisker plots. A residual is the difference between the observed value of the variable (Yi) and the predicted value of the variable Y^i. Because the variances of the residuals differ, even though the variances of the true errors are equal to each other, it is necessary to do the studentization of the residuals. When the residual is adjusted by dividing it with the standard deviation we call it as a studentized residual. , 1? ?residual dStudentize ii i h? = ? ? where h ii is the ?leverage? (a measure of the influence of the ith observation in the matrix) ranges from 0 to 1. The leverage helps to identify the influential observation. Studentized residuals will approximate a normal distribution with mean 0 and variance 1 when residual degrees of freedom for a model get large. The studentization of residuals helped to detect the outliers in each response variable. 44 Heading date data were long tailed with some extreme values. The heading dates were calculated as the interval between the date of transplanting of the seedling to the field and the date 75% of the panicle had emerged from the leaf sheath. The tiller angle and tiller diameter were normally distributed with few outliers. The tiller length data was distributed within a narrow range with few extreme values. The panicle length and panicle node numbers were normally distributed, but the panicle node number had a narrow distribution. The seed yield residual plot was funnel shaped so that one must assume some kind of trend in the data. The seed yield was much higher in year 2003-04 than 2004-05, the result of the freezing injury experienced in January 2005. The average seed mass is distributed in a very narrow range with some extreme values. All phenotypic response traits measured had higher values for the year 2003 than 2004 except for the tiller node number, panicle node number and the tiller angle (Table 2- 3). The maximum tiller angle remained the same for two years. The average and maximum heading date were more for the 2nd year of the study, likely due to the fact that the plants showed temporary dormancy in growth after exposure to the freezing temperature of January 2005. All other growth parameters like tiller diameter, length, panicle length, flag leaf length and flag leaf width were affected as well by the low temperature but seed yield and seed mass were most affected by freezing injury in 2004- 05. Multivariate analysis The first four variates from the canonical discriminant analysis all had Eigenvalues ?1 and were responsible for 84% of the total variation in the entire 45 population (Table 2-4). Heading date (r = 0.72) and tiller node number (r = 0.78) had the highest correlation with CAN 1 and tiller length (r = 0.54), tiller diameter (r = 0.55) and leaf length(r = -0.64) with CAN 2. Tiller angle (r = 0.54) and panicle length (r = -0.59) had highest correlation with CAN3 and tiller angle (r = 0.47), panicle node number (r = 0.59) and leaf width (r = 0.77) with CAN4. Accession CIav 9015 from Canada was clearly different from all other accessions in this analysis (Fig. 2-2). It is characterized by an extreme early heading date, short tillers with few nodes, yet flag leaves that are longer than most accessions evaluated (Appendix 1). This accession may in fact not belong to A. strigosa, the species under consideration, but to another member of the genus Avena. Cytogenetic and molecular studies may be needed to confirm the identity of the accession CIav 9015. Because of the large difference caused by a single accession, the relationship among the remaining 103 accessions is severely compressed (Fig. 2-2). Plotting CAN1 vs. CAN2, separated five accessions grouped together to the first quadrant of the graph with all positive values for CAN1 (tiller node number and heading date) and both positive and negative values for CAN2 (tiller diameter, tiller length and flag leaf length). While plotting CAN3 vs. CAN4, the separation of accession CIav 9015 is not prominent as in CAN1 vs. CAN2, even though the accession is distinct from all other North American accessions. The five accessions that grouped together in the previous plotting of CAN1 vs. CAN2 are dispersed in second and fourth quadrants while plotting CAN3 vs. CAN4. However the accession PI 306419 from Romania is quite distinct with 46 high positive values for CAN3. This accession is most erect (73o) with a short panicle and high tiller node number. This accession is among the ones that headed very late. Analysis of individual traits A variance analysis of the traits identified by canonical discriminant analysis as contributing significantly to the differences among accessions indicated that there were significant differences among continents, countries within continents, and accessions within countries (Table 2-5). For the user searching for suitable accession the practical question arises where to look for such accessions. As indicated earlier, heading date and the number of tiller nodes were traits highly correlated with canonical variate 1 (Table 2- 4, Fig. 2-2). As a group, accessions from Australia and Europe matured significantly later than accessions from the Mid-East and North America although individual accessions within geographic region vary greatly in heading date (Table 2-5). Some accessions from Australia and Europe headed very late, in fact too late to be useful for cover crop purposes in the southeastern USA. South American accessions on the average did not differ significantly from Australian and European accessions. Except for accession that headed before the January 2005 freeze (e.g., accession CIav 9015 from Canada) heading date among the accessions was delayed in the second year. For both years heading date was latest for accessions from Australia (data not shown). Heading date has the narrowest and widest range among the accessions from Australia and North America, respectively. Tiller node number, the second trait with a high correlation to CAN1, was consistent among the accessions from different continents. Accessions from Australia and Europe had higher tiller node numbers, consistent with their later maturity (Table 2-6). 47 There were no significant differences in tiller node number among the Middle East and the Americas and between North and South America. Tiller length, tiller diameter, and leaf length were the traits with the highest correlation with canonical variate 2 (Fig. 2-2, Table 2-4). The significance of differences among continents for tiller length (Table 2-7) mirrored those observed for heading date (Table 2-6). The tallest accession came from Australia (PI 83720) and the shortest from North America (CIav 9015). These are also the accessions with the latest and earliest heading date, respectively. The largest range in tiller length was observed among accessions from North America (Table 2-7). Based on tiller length, accessions from North and South Americas were significantly different from that of Mid-East and Europe. For tiller diameter, accessions from Australia were again significantly different from accessions from all other continents. Because of accessions CIav 9015, North America had the largest among accession difference for tiller diameter. The same accession also had the longest leaves, which were 18% (3.6 cm) longer than the leaves of the accession with the second-longest leaves. The trait means discussed thus far CIav 9015 underscore the uniqueness of this accession within the collection evaluated. Tiller angle (deviation from horizontal) and panicle length had the highest correlation (r = 0.54 and -0.59, respectively) with CAN3 (Table 2-4). Tiller angle was fairly consistent between the two years. As a group, South American accessions had the most prostrate growth habit (Table 2-8), although PI 401793 from Spain had the least tiller angle among all accessions studied (data not shown). Tiller angle varied widely within European (50?), North American (40?), and South American accessions (45?). Within country variation for tiller angle among accessions was quite narrow for Brazil 48 and Uruguay with most accessions being quite prostrate (data not shown). This may simply reflect the fact that black oat is primarily used as a cover crop in those countries. Selection for cover crop purposes would tend to favor those accession that exhibit potential to suppress weeds by denying them access to light. Tiller angle among accessions from North America was significantly different from South America. North American accessions as a group also had the largest range among accessions for panicle length (Table 2-8). Based on panicle length accessions from South America is significantly different from Europe and North America. Panicle node number and leaf width were the discriminating traits most important for CAN4 (Table 2-4, Fig. 2-2). Again accession CIav 9015 from North America was unique with respect to all accessions studied, having the least number of panicle nodes (data not shown). European accession as a group differed from all other continents except Australia (Table 2-9). As a group, Australian accessions had the broadest leaves and were significantly different from all other continents. Mid-eastern accessions not only had the narrowest leaves as a group but also the smallest range among accessions (2.1 mm). The broadest-leaved accession came from Europe (Romania, PI 361912) and the narrowest one is from South America (PI 436108). Summary and Conclusion Significant difference can be observed for traits of agronomic importance among and within countries and continents and the reason why these difference exist may be the selection of black oat for different purposes. Late heading European and Australian accessions may not be useful as cover crop in southeastern US conditions, but may be 49 useful in colder parts of the country as winter kill can be used for terminating the crop. Mostly South American accessions are with prostrate habit and are suitable for cover crop purpose in the southeastern US. The first conclusion that can be drawn from this evaluation is that there is sufficient genetic variation to begin a hybridization and selection program. The second conclusion is that the accession CIav 9015 from Canada may not belong to A. strigosa Schreb., the species under consideration, but to another member of the genus Avena. Cytogenetics studies may be useful for the conclusive identification of this accession with a doubtful identity. The third conclusion is that some traits like tiller angle are highly heritable. So this evaluation of morphology and maturity is the beginning of future breeding programs and field plot trials of the selected accessions. 50 References Andrade, E., M. Miyazawa, M. A. Pavan, and E. L. d. Oliveira. 2002. Effect of organic matter on manganese solubility. Brazilian Archives of Biology And Technology 45:17 - 20. Bauer, P. J., and D. W. Reeves. 1999. A comparison of winter cereal species and planting dates as residue cover for cotton grown with conservation tillage. Crop Sci. 39:1824-1830. Baum, B. R. 1977. Oats: wild and cultivated: A monograph of the genus Avena L. (Poaceae), p. 185-193, Vol. 14. Canada department of agriculture, Research Branch,Ontario, Canada. Ceretta, C. A., C. J. Basso, J. Diekow, C. Aita, P. S. Pavinato, F. C. B. Vieira, et al. 2002. Nitrogen fertilizer split-application for corn in no-till succession to black oats. Scientia Agricola 59:549-554. Coffman, F. A. 1977. Origin and History, p. 15-40, In F. A. Coffman, ed. Oats and Oat Improvement. American Society of Agronomy, Madison. Dilkova, M., E. N. Jellen, and R. A. Forsberg. 2000. C-banded karyotypes and meiotic abnormalities in germplasm derived from interploidy crosses in Avena. Euphytica 111:175-184. Dyck, P. L. 1966. Inheritance of stem rust resistance and other characteristics in diploid oats, Avena strigosa. Can. J. Genet. Cytol. 8:444-450. Federizzi, L. C., and C. M. Mundstock. 2004. Fodder oats: An overview for South America, p. 37-51, In J.M.Suttie and S.G.Reyynolds, eds. Fodder oats: A world overview, Vol. 33. Food and Agriculture organizations of the United Nations. 51 Katsura, M. 2004. Fodder oats in Japan, p. 145-152, In J.M.Suttie and S.G.Reynolds, eds. Fodder oats: a world overview, Vol. 33. Food and Agriculture organizations of the United Nations. Lowe, K. F., and T. M. Bowdler. 1998. Effects of height and frequecy of defoliation on the productivity of irrigated oats (Avena stigosa cv.Saia) and perennial ryegrass (Lolium perenne cv. Kangaroo Valley), grown alone or with barrel medic (Medicago truncatula cv.Jemalong). Australian journal of experimental Agriculture, 28:57-67. Martinelli, J. A. 2004. Oat diseases and their control, p. 197-214, In J.M.Suttie and S.G.Reyynolds, eds. Fodder oats: a world overview, Vol. 33. O'Mara, J. G. 1961. Cytogenetics-The fatuoid and steriloid mutations, p. 112-124, In F. A.Coffman, ed. Oats and Oat improvement. Agron. Monogr. 8. ASA, Madison, WI. Schomberg, H. H., D. M. Endale, A. Calegari, R. Peixoto, M. r. Miyazawa, and M. L. Cabrera. 2005. Influence of cover crops on potential nitrogen availability to succeeding crops in a Southern Piedmont soil. Biology and Fertility of Soils 42:299-307. Suttie, J. M., and S. G. Reynolds. 2004. Back ground to fodder oats worldwide, p. 1-7, In J.M.Suttie and S.G.Reyynolds, eds. Fodder oats: a world overview. Food and Agriculture organizations of the United Nations. Thomas, H. 1992. Cytogenetics of Avena, p. 473-507, In H.G.Marshall and M.E.Sorrells, eds. Oat Science and Technology-Agronomy monograph, Vol. 33. American Society of Agronomy, Madison, WI, U.S.A. 52 Weibull, J., L. Lyng, J. Bojensen, and V. Rasomavicius. 2005. Avena strigosa in Denmark and Lithuania: Prospects for in situ conservation. Plant Genetic Resources Newsletter 131:1 - 6. 53 Table 2-1: Materials used for the morphology and maturity study Geographic origin NPGS no. Plant ID Country State/Province Continent Vernalization CIav 1782 Russian Federation Leningrad Europe Spring CIav 2520 26-389 France Cote-d'Or Europe Spring CIav 2521 26-390 France Cote-d'Or Europe Spring CIav 2523 26-391 France Cote-d'Or Europe Spring CIav 2524 26-398 United Kingdom Wales Europe Spring CIav 2525 26-381 United Kingdom England Europe Spring PI 78821 Glabrota Australia New South Wales Australia Spring PI 83720 C. 3758 Australia New South Wales Australia Unknown PI 83721 C. 3758 Australia New South Wales Australia Unknown PI 83722 C. 3593 Australia New South Wales Australia Unknown PI 83723 C. 3756 Australia New South Wales Australia Unknown CIav 2894 United States Washington North America Spring CIav 2920 S 77 United Kingdom Wales Europe Spring CIav 2921 S 76 United Kingdom Wales Europe Spring CIav 3214 Reed's No. 590 United States New York North America Spring PI 111261 CIav 3280 Romania Cluj Europe Spring CIav 3372 S-171 Unknown South America Spring 54 Table 2-1: (cont.) PI 131695 5081 Poland Krakow Europe Spring PI 131640 7513 Poland Krakow Europe Spring PI 131641 9411 Poland Krakow Europe Spring PI 131642 9249 Poland Krakow Europe Spring CIav 4639 Saia Brazil Rio Grande do Sul South America Facultative PI 158244 typica Russian Federation Smolensk Europe Spring PI 158246 WIR 5201/1 Spain Lugo Europe Winter PI 274610 Glabrata Poland Europe Winter PI 287315 Rauhhafer aus Neustadt Germany Europe Winter PI 291990 Saia 2 Israel Mid-East Facultative PI 291991 Saia 4 Israel Mid-East Facultative PI 292226 Israel Tel Aviv Mid-East Facultative PI 304557 4659 United Kingdom Wales Europe Spring PI 436080 353 Chile Los Lagos South America Spring PI 436082 361 Chile Los Lagos South America Spring PI 436103 1 Chile Bio-Bio South America Spring PI 436104 35 Chile La Araucania South America Spring PI 436105 113 Chile La Araucania South America Spring PI 436106 117 Chile La Araucania South America Winter 55 Table 2-1: (cont.) PI 306419 2582 Romania Europe Facultative PI 361910 Romania Brasov Europe Spring PI 361911 Romania Brasov Europe Spring PI 361912 Romania Brasov Europe Spring PI 401793 Avena strigosa nuda 7 United Kingdom Europe Spring PI 401794 Avena strigosa nuda 8 United Kingdom Europe Winter PI 436107 146 Chile Bio-Bio South America Spring PI 436108 197 Chile La Araucania South America Spring PI 436109 202 Chile La Araucania South America Spring PI 436110 209 Chile La Araucania South America Spring PI 436111 218 Chile La Araucania South America Spring PI 436112 266 Chile Los Lagos South America Spring PI 436119 355 Chile Los Lagos South America Winter PI 436120 364 Chile Los Lagos South America Spring PI 436121 367 Chile Los Lagos South America Spring PI 436122 394 Chile Los Lagos South America Spring PI 436124 401 Chile Los Lagos South America Spring PI 436125 420 Chile Los Lagos South America Spring PI 436127 425 Chile Los Lagos South America Spring 56 Table 2-1: (cont.) PI 436126 423 Chile Los Lagos South America Spring PI 436130 448 Chile Los Lagos South America Spring PI 436131 449 Chile Los Lagos South America Spring PI 436132 454 Chile Los Lagos South America Spring PI 436133 507 Chile La Araucania South America Spring PI 436134 509 Chile La Araucania South America Spring PI 436113 280 Chile Los Lagos South America Spring PI 436114 302 Chile Los Lagos South America Winter PI 436115 333 Chile Los Lagos South America Winter PI 436116 335 Chile Los Lagos South America Winter PI 436117 346 Chile Los Lagos South America Spring PI 436118 354 Chile Los Lagos South America Winter CIav 9019 CD 3642 United Kingdom Wales Europe Winter CIav 9020 CD 3819 Argentina South America Mixed CIav 9021 CD 3820 Canada Ontario North America Facultative CIav 9022 CD 3916 Netherlands Europe Facultative CIav 9024 CD 4481 Germany Europe Facultative CIav 9030 CD 7497 Canada Ontario North America Winter CIav 8089 Autotetraploid of Saia United States Pennsylvania North America Winter 57 Table 2-1: (cont.) CIav 9007 CD 1002 Romania Europe Spring CIav 9011 CD 1025A Denmark Europe Spring CIav 9012 CD 1576 Bulgaria Europe Spring CIav 9014 CD 2050 Canada Ontario North America Winter CIav 9015 CD 2108 Canada Ontario North America Winter CIav 9066 CD 8088 Canada Ontario North America Facultative CIav 9110 GA 23 Canada Ontario North America Mixed CIav 9112 GA 33 Canada Ontario North America Spring CIav 9116 GA 74 Canada Ontario North America Winter PI 274608 Glabrescens Cambrica Poland Europe Facultative PI 274609 Oreadensis Arguta Poland Europe Spring CIav 9031 CD 7497A Canada Ontario North America Facultative CIav 9035 CD 7847 Russian Federation Leningrad Europe Facultative CIav 9038 CD 7853 United Kingdom Northern Ireland Europe Facultative CIav 9043 CD 7954 Argentina South America Winter CIav 9064 CD 8086 Canada Ontario North America Facultative CIav 9065 CD 8087 Canada Ontario North America Facultative PI 158245 WIR 5199 Spain Lugo Europe Spring PI 158247 WIR 5288/1 Portugal Europe Winter 58 Table 2-1: (cont.) CIav 5057 C.D. 3686 Russian Federation Former Soviet Union Europe Spring CIav 5082 C.D. 3381 Uruguay Colonia South America Spring CIav 6858 Uruguay South America Spring PI 186606 Saia Brazil Rio Grande do Sul South America Unknown CIav 6956 C.D. 3820 Canada Ontario North America Facultative CIav 7010 Saia Selection Brazil Rio Grande do Sul South America Unknown CIav 7121 C.D. 1007 Canada Ontario North America Winter CIav 7122 C.D. 920 Canada Ontario North America Winter CIav 7280 United States Maryland North America Winter CIav 8087 5201 Spain Europe Facultative SoilSaver United States Alabama North America 59 Table 2-2: Response variables studied No. Response variable Unit 1 Heading date Julian date Tiller 2 angle Degree from vertical 3 diameter mm 4 length cm 5 node number count tiller-1 6 number count plant-1 Panicle 7 length cm 8 node number count panicle-1 Flag leaf 9 length mm 10 width mm 11 Seed yield g plant-1 12 Average seed mass g 1000 seed-1 60 Table 2-3: Response variables studied and their range. No. Response variable Unit Year Max Min Average 1 Heading date Julian date 2003 195 86 170 2004 224 29 193 Tiller 2 angle Degree from vertical 2003 73.33 23.33 48.16 2004 73.33 34.67 54.10 3 diameter mm 2003 6.78 2.54 4.22 2004 5.76 1.27 3.71 4 length cm 2003 147.05 62.19 115.00 2004 140.02 49.88 96.98 5 node number count tiller-1 2003 7.73 2.21 4.72 2004 7.18 2.72 4.29 6 number count plant-1 2003 48.94 0.17 22.25 2004 28.46 1 12.04 Panicle 7 length cm 2003 44.13 18.6 30.00 2004 39.72 15.33 25.84 8 node number count panicle-1 2003 11.49 4.5 9.11 2004 10.99 3.37 8.49 Flag leaf 9 length mm 2003 220.04 60.85 108.23 2004 202.48 62.5 106.94 10 width mm 2003 1.52 0.34 0.76 2004 1.21 0.29 0.66 11 Seed yield g plant-1 2003 51.54 -0.63 8.96 2004 6.39 -0.14 1.71 12 Average seed mass g 1000 seed-1 2003 34.8 0 11.84 2004 25.47 -0.15 12.22 61 Table 2-4: Loading of Canonical Discriminant Analysis (CDA). Trait CAN1 CAN2 CAN3 CAN4 Angle -0.30 0.10 0.54 0.47 Heading 0.72 0.22 -0.16 0.01 Tiller length -0.10 0.54 0.18 0.33 Tiller diameter -0.47 0.55 0.06 0.12 Tiller node number 0.78 0.15 0.39 -0.11 Panicle length 0.37 0.37 -0.59 0.14 Panicle node number 0.20 0.17 0.18 0.59 Leaf length 0.00 -0.64 0.26 0.38 Leaf width 0.02 -0.06 0.26 0.77 Seed mass -0.40 0.01 0.38 0.31 Eigenvalues 22.59 10.53 8.73 4.04 Cumulative proportion of Eigenvalues 0.41 0.61 0.77 0.84 62 Table 2-5: Variance analysis of the traits identified by canonical discriminant analysis. These traits are contributing significantly to the differences among accessions among continents, countries within continents, and accessions within countries. Tiller Panicle Flag leaf Source Heading angle diameter length node number length node number length width --------------------------------------------- P-values --------------------------------------- Year 0.0001 0.001 0.0002 0.0001 0.0002 0.0001 0.0001 0.9728 0.0001 Continent 0.0001 0.0001 0.0001 0.0001 0.0001 0.0114 0.0005 0.0039 0.0001 Country (Continent) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 Accession (Country*Cont) 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 63 Table 2-6: Traits with high correlation to CAN1 among different accessions. CAN 1 is responsible for 41 % of total variation. Pair-wise comparisons identified the significant difference among accessions based on these traits among different continents Pair-wise differences and P-values Continent Mean SE Range Australia Europe Mid- East North America South America Heading date Australia 10-May 12.3 27-Apr-28 May 6 25 18 9 Europe 4-May 11.7 5-Mar-13-Jun 0.602 19 12 3 Mid-East 15-Apr 12.7 27-Mar-11-May <0.001 0.002 -7 -16 North America 22-Apr 11.8 30-Nov-1-Jun <0.001 <0.001 0.646 -9 South America 1-May 11.7 27-Mar-11-Jun 0.150 0.418 0.018 0.004 Tiller node number Australia 5.6 0.22 4-7 0.94 1.65 1.49 1.36 Europe 4.7 0.20 3-8 <0.001 0.71 0.55 0.42 Mid-East 4.0 0.22 4-4 <0.001 <0.001 -0.16 -0.28 North America 4.1 0.20 2-6 <0.001 <0.001 0.639 -0.12 South America 4.3 0.20 3-6 <0.001 <0.001 0.075 0.218 64 Table 2-7: Traits with high correlation to CAN 2 among different accessions. CAN 2 is responsible for 20% of total variation. The significance of differences among continents for tiller length is similar to those observed for heading date (Table 2-6). Pair-wise differences and P-values Continent Mean SE Range Australia Europe Mid- East North America South America Tiller length, cm Australia 108 10.5 85-147 -7.64 -9.11 2.19 -0.32 Europe 116 10.3 78-143 0.003 -1.47 9.83 7.32 Mid-East 117 10.5 98-133 0.021 0.969 11.30 8.79 North America 106 10.3 50-132 0.850 <0.001 <0.001 -2.51 South America 109 10.3 66-144 1.000 <0.001 0.002 0.259 Tiller diameter, mm Australia 3.5 0.21 2.9-5.0 -0.42 -1.06 -0.47 -0.77 Europe 4.0 0.19 2.4-7.0 0.001 -0.64 -0.05 -0.35 Mid-East 4.6 0.22 3.9-5.0 <0.001 <0.001 0.59 0.29 North America 4.0 0.19 1.3-6.0 <0.001 0.947 <0.001 -0.3019 South America 4.3 0.19 2.4-6.0 <0.001 <0.001 0.088 <0.001 Leaf length, mm Australia 113 3.5 88-165 4.94 20.63 -3.49 13.16 Europe 108 1.4 61-186 0.645 15.70 -8.43 8.22 Mid-East 93 4.0 85-103 <0.001 0.001 -24.13 -7.47 North America 117 1.9 63-220 0.885 0.001 <0.001 16.65 South America 100 1.3 76-169 0.002 <0.001 0.346 <0.001 65 Table 2-8: Traits with high correlation to CAN 3 among different accessions. CAN 3 is responsible for 16 % of total variation. European accessions have broadest range for tiller angle among themselves. Tiller angle among accessions from North America was significantly different from South America. Pair-wise differences and P-values Continent Mean SE Range Australia Europe Mid- East North America South America Tiller angle, ? from horizontal Australia 56 3.8 43-68 4.92 -3.74 0.63 7.55 Europe 51 3.0 23-73 0.338 -8.67 -4.29 2.63 Mid-East 60 4.3 57-67 0.878 0.064 4.37 11.30 North America 56 3.1 32-73 0.999 0.065 0.702 6.92 South America 49 3.0 27-72 0.035 0.245 0.006 <0.001 Panicle length, cm Australia 30 2.3 24-39 0.56 1.86 0.84 2.04 Europe 29 2.3 21-40 0.790 1.29 0.28 1.47 Mid-East 28 2.3 24-31 0.063 0.131 -1.01 0.18 North America 29 2.3 15-44 0.493 0.882 0.397 1.19 South America 28 2.3 17-35 0.000 <0.001 0.997 0.001 66 Table 2-9: Traits with high correlation to CAN 4 among different accessions. CAN 4 is responsible for 7 % of total variation. Pair-wise comparisons identified the significant difference of European accessions from accessions of all other continents except Australia. Pair-wise differences and P-values Continent Mean SE Range Australia Europe Mid- East North America South America Panicle node number Australia 9.2 0.28 8.0-11.0 0.13 0.86 0.77 0.46 Europe 9.1 0.25 7.0-11.0 0.871 0.73 0.64 0.33 Mid-East 8.4 0.29 8.0-9.0 <0.001 <0.001 -0.09 -0.40 North America 8.5 0.26 3.0-11.0 <0.001 <0.001 0.977 -0.31 South America 8.8 0.25 7.0-11.0 0.006 <0.001 0.062 0.001 Leaf width, mm Australia 8.62 0.51 5.9-12.3 1.186 1.84 1.10 1.97 Europe 7.44 0.45 3.1-15.2 <0.001 0.656 -0.081 0.782 Mid-East 6.78 0.53 6.1-8.2 <0.001 0.200 -0.737 0.126 North America 7.52 0.46 3.3-14.2 0.001 0.986 0.139 0.864 South America 6.66 0.45 2.9-12.5 <0.001 <0.001 0.993 <0.001 67 Figure 2-1: Primary (circle) and secondary (rectangle) centers of origin of black oats. 68 -17 -12 -7 -2 3 -12 -7 -2 3 8 CAN1 (41 % of total variation) CA N2 (2 0 % of to tal va ria tio n) . Australia Europe Mid-East North America South America -17 -12 -7 -2 3 -12 -7 -2 3 8 CAN3 (16 % of total variation) CA N4 (7 % of to tal va ria tio n) . Australia Europe Mid-East North America South America Figure 2-2: Canonical discriminant analysis scatter plot separates the accessions originated in different geographical locations into meaningful groups. In the first panel accession CIav 9015 separated to the extreme left of second quadrant. CAN1 vs. CAN2 separates five accessions to the extreme right of the first quadrant. 69 III. PLOT TRIALS IN BLACK OAT (AVENA STRIGOSA SCHREB.) FOR BIOMASS, GRAIN YIELD AND TEST WEIGHT Abstract Even though more than 100 black oat accessions are available from USDA for research purpose the only commercially available black oat cultivar in US is the SoilSaver. In this pioneering study we compared the biomass, grain production and test weight of SoilSaver to the other selected black oat accessions. Eighteen accessions were selected for biomass, grain yield and test weight study based on their relative maturity to that of SoilSaver and the availability of enough seeds from 15 to18 plants. The studies were conducted in 2004-05 and 2006-07. The biomass study was conducted in four locations with two replications in each location and grain yield and test weight study was conducted in two locations in the first year and five locations in the second year with three replicates at each location. Mixed model method by invoking PROC MIXED procedure of SAS? (SAS Institute, Cary, NC) was used for the analysis of variance. The differences of the least squares means of accessions and the SoilSaver control calculated with the ?Dunnett? adjustment gave a clear comparison of the performance of different accessions based on biomass and grain yield and test weight to that of SoilSaver control. 70 The study revealed the superiority of SoilSaver in biomass and grain yield production, but identified many accessions with higher test weight. Introduction Black oat (A. strigosa Schreb) has recently emerged as an important winter cover crop and forage crop suitable for subtropical and temperate regions of the world (Suttie and Reynolds, 2004). In South America black oat is grown extensively for cover crop and forage purposes (Federizzi and Mundstock, 2004). It has the potential to produce comparable amount of biomass to other leguminous and non-leguminous cover crops. Biomass production and soil N mineralization dynamics of Black oat are on par with that of crimson clover (Schomberg et al., 2005). A study conducted in Brazil demonstrated the ability of cover crop residues of black oat to decrease the manganese toxicity in well aerated acid soils by lowering the Mn solubility (Andrade et al., 2002). Obviously, the kill date has an effect on biomass yield and nitrogen availability of cover crops and maximizing the window between establishment and kill may increase the biomass production and nutrient accumulation. Delayed kill date of hairy vetch for two weeks improved N accumulation significantly (Sainju and Singh, 2001). Black oat reached maximum biomass at anthesis compared to rye (Secale cereale L.), and wheat (Triticum aestivum L.) that continued to increase biomass significantly through soft dough stage (Ashford and Reeves, 2003). Cotton lint yield following black oat was higher than that following rye, even though rye produces more biomass than black oat (Bauer and Reeves, 1999). But low night temperature for a longer period of time has a negative influence on biomass production in black oat compared to rye (Reeves et al., 2005). 71 Even though more 100 black oat accessions are available from USDA germplasm unit for research purpose the only commercially available black oat cultivar in the United States is ?SoilSaver?, which was released by Auburn University and USDA in 2002. In this paper we are comparing the biomass production, grain yield and test weight of selected black oat accessions based on the preliminary results from a previous study of the entire USDA black oat accessions for agronomic and morphological traits to that of SoilSaver. . Materials and Methods Accessions were selected based on their relative heading date to that of SoilSaver (? 2 weeks) and adequate seed yield from 15-18 plants. The 18 accessions selected have 9 different countries of origin (Brazil, Bulgaria, Canada, Chile, Denmark, Israel, Poland, Romania and United States). For the 2004-05 study the accessions were planted as 5' X 10' row plots on last week of October and first week of November, 2004. The plots were harvested on first week of April, 2005. For the 2004-05 biomass study the entire plot weight was taken in a once-over harvesting scheme when the majority of entries were fully headed. A plot combine was used for grain harvest. Harvested grain was dried to < 10% moisture and cleaned with an Airblast Cleaner (ALMACO Inc., Nevada, Iowa) and meshed sieves of different sizes. For the biomass study the accessions were planted at four locations in Alabama: 1) Plant Breeding Unit (PBU), Tallassee, Alabama, (32?24.5'N, 85?57'W), where the soil type is fine sandy loam, 2) Tennessee Valley Research and Extension Center (TVS), Belle Mina, Alabama (34?41'N, 86?53'W) where 72 the soil type is Decatur silt loam (fine, kaolinitic, thermic, Rhodic, Paleudults.), 3) Wiregrass Research and Extension Center (WGS), Headland (31?21'N, 85?21' uniF020W,) where the major soil type is Dothan sandy loam, and 4) Gulf Coast Research and Extension Center (GCS), Fairhope (30?33' N, 87?81 ' W) where the soil type is Malbis sandy loam. Two replicates were planted in each location for the biomass study. The locations for grain yield and test weight study are 1) Plant Breeding Unit, Tallassee, Alabama and 2) Prattville Agricultural Research Unit (PEF), Prattville, Alabama (32?42' 40'' N, 86?44' 38'' W) where the major soil type is Lucedale sandy loam. Three replicates were planted in each location for grain yield and test weight studies. The experiments were repeated in 2006, but this time with more locations for grain yield and test weight studies. The biomass study was conducted at four locations 1) Gulf Coast Research and Extension Center (GCS, 2) Plant Breeding Unit (PBU), 3) Tennessee Valley Research and Extension Center (TVS) and 4) Prattville Agricultural Research Unit (PEF). Two replicates were planted at each location for the biomass study. The grain yield and test weight studies were conducted at five locations of Alabama viz. 1) Gulf Coast Research and Extension Center (GCS), 2) Plant Breeding Unit, (PBU) 3) Tennessee Valley Research and Extension Center (TVS), 4) Prattville Agricultural Research Unit (PEF) and 5) Wiregrass Research and Extension Center (WGS). Three replicates were planted at each location for the grain yield and test weight studies. The plots were harvested during the last week of May, 2007 and processed as described earlier. 73 Statistical Analysis Mixed model methodology as implemented in PROC MIXED of SAS?(SAS Institute, Cary, NC) was used to analyze the data using a nearest neighbor analysis model. First we calculated the residuals using the Proc Mixed procedure. A residual is the difference between the observed value of the variable (Yi) and the predicted value of the variable Y^i. The covtest option in proc mixed produces asymptotic standard errors and Wald Z-tests for the covariance parameter estimates. The Wald Z is a common likelihood- based statistic, which is computed as the parameter estimate divided by its asymptotic standard error. The asymptotic standard errors are computed from the inverse of the second derivative matrix of the likelihood with respect to each of the covariance parameters. A mean nearest neighbor distance ( d ) was calculated by taking the mean of residuals of the four plots surrounding each plot and used in the mixed model analysis using PROC MIXED procedure of SAS? (SAS institute, Cary, NC) for nearest neighbor adjustment. The mean nearest neighbor distance d = N di N i ? =1 , where N is the number of points, di is the nearest neighbor distance for point i. The Kenward-Roger method was used for the estimation of degrees of freedom. For each of the three response variables we calculated least squares interaction means listed in (Tables 3-4, 3-5, 3-6, 3-7 & 3-8). Block within location, mean nearest neighbor distance, location, accession and location x accession interactions were taken as the fixed effects in the model for the 2004-05 study. Block within location, location, accession and location x accession interactions were taken as the fixed effects in the model for the 2006-07 study. The differences of the least squares means of accessions and the SoilSaver control were calculated with the ?Dunnett? 74 adjustment. The Dunnett?s test is useful when the only pair-wise comparisons of interest are comparisons with a control. The Dunnett?s test is an exact test, because it?s family- wise error rate (FWE) is exactly equal to? , for balanced as well as unbalanced one-way designs and hence it reduces the type I error. The yield of SoilSaver at standard seeding rate (90 lbs acre-1) was taken as the reference point or control in this experiment. The difference in least square means with that of the control were plotted for biomass, grain yield and test weight. Results and Discussion Biomass Yield SoilSaver at standard seeding rate (90 lbs acre-1) was used as a control for this evaluation. SoilSaver at standard seeding rate produced 8769 kg ha-1, 11683 kg ha-1, 3997 kg ha-1 and 4088 kg ha-1 of biomass at Gulf Coast Research and Extension Center, Plant Breeding Unit, Tennessee Valley Research and Extension Center and Wiregrass Research and Extension Center respectively (Table 3-4) during 2004-05 study. Accessions CIav 8089 produced significantly higher biomass yield than SoilSaver at standard seeding rate at Tennessee Valley (P= 0.0167) and Wiregrass (P=0.001). Accessions PI 111261 except at Wiregrass, CIav 9110 except at Tennessee Valley, and CIav 9112 except at Wiregrass, performed poorer than SoilSaver at standard seeding rate. During the 2006-07 study SoilSaver at standard seeding rate produced 6562 kg ha-1, 6552 kg ha-1, 1473 kg ha-1 and 10433 kg ha-1 of biomass at Gulf Coast Research and Extension Center, Plant Breeding Unit, Tennessee Valley Research and Extension Center 75 and Prattville Agricultural Research Unit, respectively (Table 3-5). None of the accessions are significantly different from SoilSaver in biomass production at Gulf Coast Research and Extension Center, Plant Breeding Unit and Prattville Agricultural Research Unit. At Tennessee Valley Research and Extension Center Accession CIav 2520 from France (P = 0.02) produced higher biomass yield than the control. Grain yield Grain yield was not consistent across the two locations (Plant Breeding Unit, Tallassee, Alabama and Prattville Agricultural Research Unit, Prattville, Alabama) for the 2004-05 study. SoilSaver at standard seeding rate (90 lbs acre-1) was used as a control for this evaluation. SoilSaver at standard seeding rate produced 1013 kg ha-1 and 652 kg ha-1 grain yield at Plant Breeding Unit (PBU) and Prattville Agricultural Research Unit respectively (Table 3-6). The severe lodging experienced in Prattville was responsible for the low grain production there during 2004-05. Accessions PI 436103, PI 436104 and CIav 7010 performed better than the control in both locations. At PBU, accessions CIav 2520 (P < 0.001), CIav 9007 (P < 0.001), CIav 9012 (P < 0.001) and CIav 9112 (P = 0.001) performed poorer than the control and accessions PI 291991 (P < 0.01), PI 436103 (P < 0.001), PI 436104 (P = 0.05), PI 274608 (P < 0.001) and CIav 7010 (P = 0.02) performed better than the control. At PEF accessions PI 436103 (P = 0.03), PI 436104 (P < 0.001), PI 436105 (P = 0.02), PI 436114 (P = 0.003) and CIav 7010 (P = 0.001) performed better than the control. 76 During the 2006-07 study, SoilSaver at standard seeding rate produced 1662 kg ha-1, 1650 kg ha-1, 822 kg ha-1, 1130 kg ha-1, and 344 kg ha-1 of grain yield at Gulf Coast Research and Extension Center (GCS), Plant Breeding Unit (PBU), Prattville Agricultural Research Unit (PEF), Tennessee Valley Research and Extension Center (TVS) and Wiregrass Research and Extension Center (WGS) respectively (Table 3-7). During 2006-07 study at GCS accessions PI 274608 (P = 0.02) and CIav 9112 (P = 0.07) produced significantly lower grain yield than control. At PBU all the accessions except PI 436080 and CIav 9011 differed significantly from SoilSaver in grain production. Among those significantly different accessions, all but SoilSaver_45 (SoilSaver at half the standard seeding rate) produced lower grain yield than SoilSaver at standard seeding rate. At PEF and TVS none of the accessions differ significantly from control. At WGS accession at SoilSaver_45 (P = 0.01) produced significantly higher grain yield than control. Test weight During the 2004-05 study SoilSaver at standard seeding rate has test weight of 27.5 lbs bu-1and 32.1 lbs bu-1 at Plant Breeding Unit (PBU), and Prattville Agricultural Research Unit (PEF), respectively (Table 3-6). Accessions PI 291991, PI 436103, PI 436104, PI 436105, PI 436110, PI 436114, CIav 8089, PI 274608, and CIav 7010 had higher test weight than the control at both locations. Accessions PI 111261 performed poorer than the control at the two locations. During the 2006-07 study SoilSaver at standard seeding rate had a test weight of 18.6 lbs bu-1, 25.3 lbs bu-1, 25.8 lbs bu-1, 24.1 lbs bu-1 and 19.0 lbs bu-1 at Gulf Coast 77 Research and Extension Center (GCS), Plant Breeding Unit (PBU), Prattville Agricultural Research Unit (PEF), Tennessee Valley Research and Extension Center (TVS), and Wiregrass Research and Extension Center (WGS) respectively (Table 3-8). At GCS accession CIav 8089 (P = 0.08) has significantly higher test weight than SoilSaver. Accession PI 436103 (P = 0.06) has significantly lower test weight than SoilSaver. At PEF accessions PI 291991 (P = 0.01), PI 436103 (P = 0.01), PI 436104 (P = 0.01), PI 436110 (P = 0.05), PI 436114 (P = 0.04), CIav 8089 (P = 0.01) and CIav 7010 (P = 0.01) differ significantly from SoilSaver at standard seeding rate. At TVS accessions CIav 2520 (P < 0.001), PI 291991 (P < 0.001), PI 436103 (P < 0.001), PI 436104 (P < 0.001), PI 436105 (P = 0.07), PI 436110 (P < 0.001), PI 436114 (P < 0.001), CIav 8089 (P < 0.001), CIav 9007 (P = 0.005), CIav 9110 (P = 0.06), CIav 9112 (P < 0.001), PI 274608 (P = 0.012) and CIav 7010 (P < 0.001) show significantly higher test weight than SoilSaver at standard seeding rate. At WGS accessions PI291991 (P < 0.001), PI 436103 (P < 0.001), PI 436104 (P < 0.001), PI 436105 (P < 0.001), PI 36110 (P < 0.001), PI436114 (P < 0.001), CIav 8089 (P < 0.001), PI 274608 (P = 0.03) and CIav 7010 (P < 0.001) has significantly higher test weight than control. Conclusions Based on the 2004-05 and 2006-07 study it is found that none of the accessions performed better than SoilSaver in biomass production consistently at all the four locations. None of the accessions performed significantly better than SoilSaver in grain yield production consistently in all locations during 2006-07 study. This evaluation 78 identified many accessions having higher test weight than SoilSaver. Overall SoilSaver performed better than most of the accessions studied in all the aspects. 79 References Andrade, E., M. Miyazawa, M. A. Pavan, and E. L. d. Oliveira. 2002. Effect of organic matter on manganese solubility. Brazilian Archives Of Biology And Technology 45:17 - 20. Ashford, D. L., and D. W. Reeves. 2003. Use of a mechanical roller-crimper as an alternative kill method for cover crops. American Journal of Alternative Agriculture 18(1):37-45. Bauer, P. J., and D. W. Reeves. 1999. A comparison of winter cereal species and planting dates as residue cover for cotton grown with conservation tillage. Crop Science 39:1824-1830. Federizzi, L. C., and C. M. Mundstock. 2004. Fodder oats: An overview for South America, p. 37-51, In J.M.Suttie and S.G.Reyynolds, eds. Fodder oats: A world overview, Vol. 33. Food and Agriculture organizations of the United Nations. Reeves, D. W., A. J. Price, and M. G. Patterson. 2005. Evaluation of three winter cereals for weed control in conservation-tillage nontransgenic cotton. Weed Technology 19:731-736. Sainju, U. M., and B. P. Singh. 2001. Tillage, Cover Crop, and Kill-Planting Date Effects on Corn Yield and Soil Nitrogen. Agron. J. 93:878-886. Schomberg, H. H., D. M. Endale, A. Calegari, R. Peixoto, M. Miyazawa, and M. L. Cabrera. 2005. Influence of cover crops on potential nitrogen availability to succeeding crops in a Southern Piedmont soil. Biology and Fertility of Soils 42:299-307. 80 Suttie, J. M., and S. G. Reynolds. 2004. Back ground to fodder oats worldwide, p. 1-7, In J.M.Suttie and S.G.Reyynolds, eds. Fodder oats: a world overview. Food and Agriculture Organizations of the United Nations. 81 Table 3-1: Materials used for the Biomass and grain yield studies Geographic origin NPGS no. Plant ID Country State/Province Continent CIav 2520 26-389 France Cote-d'Or Europe CIav 7010 Saia Selection Brazil Rio Grande do Sul South America CIav 8089 Autotetraploid of Saia United States Pennsylvania North America CIav 9007 CD 1002 Romania Europe CIav 9011 CD 1025A Denmark Europe CIav 9012 CD 1576 Bulgaria Europe CIav 9110 GA 23 Canada Ontario North America CIav 9112 GA 33 Canada Ontario North America CIav 9116 GA 74 Canada Ontario North America PI 111261 CIav 3280 Romania Cluj Europe PI 274608 Glabrescens Cambrica Poland Europe PI 291991 Saia 4 Israel Mid-East PI 436080 353 Chile Los Lagos South America PI 436103 1 Chile Bio-Bio South America PI 436104 35 Chile La Araucania South America PI 436105 113 Chile La Araucania South America PI 436110 209 Chile La Araucania South America PI 436114 302 Chile Los Lagos South America SoilSaver United States Alabama North America 82 Table 3-2: Variance analysis of the biomass, grain yield and test weight studies of 2004-05 studies Source Biomass Grain yield Test weight GCS PBU TVS WGS PBU PEF PBU PEF ---------------------------------------------------P-value----------------------------------------------- Rep 0.0002 0.0045 0.8761 0.2346 0.0601 0.0079 0.0053 0.0001 Nearest neighbor distance 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 Accession 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 83 Table 3-3: Variance analysis of the biomass, grain yield and test weight studies of 2006-07 studies Biomass Grain yield Test weight Location Rep Accession Rep Accession Rep Accession .-------------------------------P P value----------------------------- GCS 0.004 0.237 0.335 0.000 0.000 0.147 PBU 0.026 0.797 0.260 0.000 0.001 0.531 TVS 0.563 0.004 0.004 0.025 0.511 0.000 PEF 0.031 0.213 0.276 0.028 0.765 0.000 WGS - - 0.443 0.008 0.060 0.000 84 Table 3-4: LS means of biomass study 2004-05 at four locations. 1) Gulf Coast Research and Extension Center, Fairhope 2) Plant Breeding Unit, 3) Tennessee Valley Research and Extension Center, and 4) Wiregrass Research and Extension Center. GCS EVS TVS WGS Accession Estimate SE Estimate SE Estimate SE Estimate SE SoilSaver_90 8769 174 11683 375 3997 133 4088 94 As_016 7067 250 8653 524 2843 187 3803 133 As_028 9566 248 11199 526 4505 187 4179 136 As_031 8188 247 13436 524 3834 188 4756 109 As_033 8974 249 10638 526 4688 188 4362 109 As_034 9568 249 11260 524 4638 188 4497 112 As_035 9514 247 9913 537 4734 188 4374 133 As_046 7618 247 10360 524 4836 187 4189 112 As_063 10788 250 11144 525 4370 209 4304 134 As_074 8926 247 12014 524 4873 188 5117 135 As_075 7238 249 12338 524 2802 187 3456 133 As_076 7954 250 10140 525 3025 188 2871 143 As_077 6574 248 10172 526 3740 188 4373 137 As_081 7745 247 8674 525 3728 188 3303 134 As_082 7373 247 8705 524 3154 188 3693 133 As_083 8004 248 10828 524 3580 188 3463 133 As_084 10385 247 12053 527 4150 190 4549 133 As_099 8606 247 11783 524 4947 187 4623 133 SoilSaver_45 9320 248 10790 524 3288 188 4221 134 85 Table 3-5: LS means of biomass study 2006-07 at four locations. 1) Gulf Coast Research and Extension Center, Fairhope 2) Plant Breeding Unit, Tallassee, 3) Prattville Agricultural Research Unit and 4) Tennessee Valley Research and Extension Center. GCS PBU PEF TVS Accession Estimate SE Estimate SE Estimate SE Estimate SE SoilSaver_90 6562 971 6552 1846 10433 1366 1473 104 CIav 2520 6807 971 5567 1846 11010 1366 2005 104 PI 111261 6270 971 7624 1846 9414 1366 1314 104 PI 291991 7279 971 6951 1846 12690 1366 1447 104 PI 436080 6527 971 9458 1846 11387 1366 1571 104 PI 436103 6656 971 10211 1846 10124 1366 1489 104 PI 436104 6401 971 5773 1846 13049 1366 1509 104 PI 436105 6199 971 7347 1846 12896 1366 1448 104 PI 436110 7935 971 8265 1846 9229 1366 1536 104 PI 436114 7960 971 5314 1846 11461 1366 1564 104 CIav 8089 7536 971 6071 1846 9312 1366 1400 104 CIav 9007 7107 971 9781 1846 9841 1366 1356 104 CIav 9011 3957 971 8509 1846 8638 1366 1514 104 CIav 9012 7264 971 9273 1846 10173 1366 1249 104 CIav 9110 5947 971 8260 1846 6600 1366 1157 104 CIav 9112 4571 971 7919 1846 9666 1366 1657 104 CIav 9116 6673 971 10168 1846 10486 1366 1278 104 PI 274608 4194 971 8313 1846 11790 1366 1319 104 CIav 7010 7142 971 6562 1846 12423 1366 1687 104 SoilSaver_45 5150 971 8145 1846 8822 1366 1767 104 86 Table 3-6: LS means of grain yield and test weight study 2004-05 at 1) Plant Breeding Unit, and 2) Prattville Agricultural Research Unit. Grain yield Test weight PBU PEF PBU PEF Accession Estimate SE Estimate SE Estimate SE Estimate SE SoilSaver_90 1013 73 652 91 27.5 0.4 32.1 0.4 As_002 488 85 652 91 24.9 0.4 37.9 0.6 As_016 738 85 1089 140 25.2 0.4 28.9 0.8 As_028 1675 84 392 138 36.3 0.4 37.1 0.6 As_031 1147 84 468 137 24.7 0.4 31.6 0.8 As_033 1490 85 480 137 39.0 0.4 38.5 0.6 As_034 1353 84 1199 137 37.9 0.4 39.8 0.6 As_035 1175 84 1571 137 37.1 0.4 37.1 0.6 As_046 1353 84 1227 137 36.8 0.4 36.9 0.6 As_063 1154 84 949 137 35.1 0.4 37.6 0.6 As_074 1240 84 1325 137 35.9 0.4 36.3 0.6 As_075 555 85 986 137 24.3 0.4 31.4 0.6 As_076 921 84 266 137 27.1 0.4 30.8 0.6 As_077 563 73 867 138 24.8 0.4 31.2 0.8 As_081 709 84 671 169 24.9 0.4 28.8 0.6 As_082 513 104 543 137 23.5 0.5 29.6 0.8 As_083 720 85 724 170 23.7 0.4 As_084 1447 73 783 137 31.7 0.4 35.8 0.6 As_099 1381 73 1392 137 36.9 0.4 37.5 0.6 SoilSaver_45 1080 84 949 138 26.8 0.4 31.5 0.6 87 Table 3-7: LS means of grain yield study 2006-07 at five locations. 1) Gulf Coast Research and Extension Center, Fairhope 2) Plant Breeding Unit, Tallassee 3) Prattville Agricultural Research Unit and 4) Tennessee Valley Research and Extension Center 5) Wiregrass Research and Extension Center. GCS PBU PEF TVS WGS Accession Estimate SE Estimate SE Estimate SE Estimate SE Estimate SE SoilSaver_90 1662 142 1650 80 822 164 1130 227 344 144 CIav 2520 1661 142 748 80 850 164 1567 227 259 144 PI 111261 1410 142 800 80 712 164 1043 227 246 144 PI 291991 1142 142 421 80 1343 164 1553 227 554 144 PI 436080 1933 142 1475 80 857 202 776 227 893 144 PI 436103 1424 142 193 80 1113 164 1640 227 724 144 PI 436104 1469 142 277 80 1301 164 1696 227 518 178 PI 436105 1670 142 665 80 1097 164 1768 227 527 144 PI 436110 1386 142 247 80 1177 164 1337 227 535 144 PI 436114 1202 142 282 80 1091 164 1303 227 576 144 CIav 8089 1394 142 257 80 1331 164 1690 227 773 144 CIav 9007 1567 142 924 80 771 164 1341 227 570 144 CIav 9011 1415 142 1360 80 698 164 1073 227 360 144 CIav 9012 1123 142 879 99 811 164 984 227 379 144 CIav 9110 1406 142 859 80 720 164 687 227 285 144 CIav 9112 1082 142 710 80 846 164 1260 227 269 144 CIav 9116 1368 142 790 80 790 164 773 227 304 144 PI 274608 962 142 282 80 1053 164 987 227 462 144 CIav 7010 1253 142 317 80 1316 164 1251 227 517 144 SoilSaver_45 1979 142 1655 80 658 164 1067 227 1116 144 88 Table 3-8: LS means of test weight study 2006-07 at five locations. 1) Gulf Coast Research and Extension Center, Fairhope 2) Plant Breeding Unit, Tallassee, 3) Prattville Agricultural Research Unit and 4) Tennessee Valley Research and Extension Center 5) Wiregrass Research and Extension Center. GCS PBU PEF TVS WGS Accession Estimate SE Estimate SE Estimate SE Estimate SE Estimate SE SoilSaver_90 18.6 2.3 25.4 1.1 25.8 2 24.1 0.9 19.1 0.6 CIav 2520 20.2 2.3 24.4 1.1 30.3 2 30.7 0.9 20.9 0.8 PI 111261 19.1 2.3 24.7 1.1 27.1 2 25.7 0.9 19.7 0.8 PI 291991 22.8 2.3 23.3 1.1 36.1 2 32.3 0.9 27.6 0.6 PI 436080 18.5 2.3 24.0 1.1 25.8 2.5 23.2 0.9 20.0 0.6 PI 436103 22.7 2.3 19.8 1.4 36.6 2 33.7 0.9 26.2 0.6 PI 436104 23.2 2.3 23.6 1.4 37.0 2 34.3 0.9 27.5 0.8 PI 436105 21.8 2.3 23.7 1.1 32.6 2 28.0 0.9 26.4 0.6 PI 436110 23.0 2.3 22.4 1.4 34.5 2 34.7 0.9 27.8 0.6 PI 436114 22.9 2.3 23.6 1.1 34.8 2 34.5 0.9 27.8 0.6 CIav 8089 28.1 2.3 23.4 1.4 36.0 2 32.9 0.9 27.8 0.6 CIav 9007 20.2 2.3 24.6 1.1 28.9 2 29.3 0.9 21.3 0.8 CIav 9011 18.7 2.3 24.7 1.1 25.6 2 24.8 0.9 19.5 0.6 CIav 9012 23.5 2.3 23.8 1.4 27.3 2 26.7 0.9 20.5 0.6 CIav 9110 24.0 2.3 22.3 1.1 25.6 2 28.0 0.9 20.2 0.6 CIav 9112 19.0 2.3 22.6 1.1 28.6 2 30.9 0.9 21.7 0.8 CIav 9116 23.3 2.3 23.3 1.1 26.2 2 26.6 1.1 20.3 0.6 PI 274608 20.3 2.3 23.3 1.4 29.7 2 28.8 0.9 21.9 0.6 CIav 7010 27.8 2.3 25.0 1.1 36.0 2 32.3 0.9 25.0 0.6 SoilSaver_45 18.5 2.3 24.6 1.1 18.1 2 23.7 0.9 19.7 0.6 89 -2500 -2000 -1500 -1000 -500 0 500 1000 1500 2000 2500 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-1: Biomass study 2004-05 at Gulf Coast Research and Extension Center, Fairhope. The biomass yield of SoilSaver at standard seeding rate is 8769 kg ha-1 with a SED of 174. 90 -3000 -2500 -2000 -1500 -1000 -500 0 500 1000 1500 2000 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-2: Biomass study 2006-07 at Gulf Coast Research and Extension Center, Fairhope. The biomass yield of SoilSaver at standard seeding rate is 6562 kg ha-1 with a SED of 971. 91 -4000 -3000 -2000 -1000 0 1000 2000 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-3: Biomass study 2004-05 at Plant Breeding Unit, Tallassee, Alabama. The biomass yield of SoilSaver at standard seeding rate is 11683 kg ha-1 with a SED of 374. 92 -2000 -1000 0 1000 2000 3000 4000 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-4: Biomass study 2006-07 at Plant Breeding Unit, Tallassee, Alabama. The biomass yield of SoilSaver at standard seeding rate is 6552 kg ha-1 with a SED of 1846. 93 -1500 -1000 -500 0 500 1000 1500 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-5: Biomass study 2004-05 at Tennessee Valley Research and Extension Center, Belle Mina. The biomass yield of SoilSaver at standard seeding rate is 3997 kg ha-1 with a SED of 133 94 -400 -300 -200 -100 0 100 200 300 400 500 600 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-6: Biomass study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina. The biomass yield of SoilSaver at standard seeding rate is 1473 kg ha-1 with a SED of 104. 95 -1500 -1000 -500 0 500 1000 1500 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-7: Biomass study 2004-05 at Wiregrass Research and Extension Center, Headland. The biomass yield of SoilSaver at standard seeding rate is 4088 kg ha-1 with a SED of 94. 96 -10000 -8000 -6000 -4000 -2000 0 2000 4000 6000 8000 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-8: Biomass study 2006-07 at Prattville Agricultural Research Unit. The biomass yield of SoilSaver at standard seeding rate is 10433 kg ha-1 with a SED of 1366. 97 -600 -400 -200 0 200 400 600 800 1000 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-9: Grain yield study 2004-05 at Prattville Agricultural Research Unit, Prattville, Alabama. The grain yield of SoilSaver at standard seeding rate is 652 kg ha-1 with a SED of 91. 98 -200 -100 0 100 200 300 400 500 600 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-10: Grain yield study 2006-07 at Prattville Agricultural Research Unit, Prattville, Alabama. The grain yield of SoilSaver at standard seeding rate is 822 kg ha-1 with a SED of 164. 99 -600 -400 -200 0 200 400 600 800 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-11: Grain yield study 2004-05 at Plant Breeding Unit, Tallassee, Alabama. The grain yield of SoilSaver at standard seeding rate is 1013 kg ha-1 with a SED of 73. 100 -1600 -1400 -1200 -1000 -800 -600 -400 -200 0 200 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-12: Grain yield study 2006-07 at Plant Breeding Unit, Tallassee, Alabama. The grain yield of SoilSaver at standard seeding rate is 1650 kg ha-1 with a SED of 80. 101 -800 -600 -400 -200 0 200 400 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-13: Grain yield study 2006-07 at Gulf Coast Research and Extension Center, Fairhope. The grain yield of SoilSaver at standard seeding rate is 1662 kg ha-1 with a SED of 142. 102 -600 -400 -200 0 200 400 600 800 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-14: Grain yield study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina. The grain yield of SoilSaver at standard seeding rate is 1130 kg ha-1 with a SED of 227. 103 -200 -100 0 100 200 300 400 500 600 700 800 900 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-15: Grain yield study 2006-07 at Wiregrass Research and Extension Center, Headland. The grain yield of SoilSaver at standard seeding rate is 344 kg ha-1 with a SED of 144. 104 -4 -2 0 2 4 6 8 10 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-16: Test weight study 2004-05 at Prattville Agricultural Research Unit, Prattville. The grain yield of SoilSaver at standard seeding rate is 32.1 lbs bu-1 with a SED of 0.4. 105 -10 -5 0 5 10 15 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-17: Test weight study 2006-07 at Prattville Agricultural Research Unit, Prattville. The grain yield of SoilSaver at standard seeding rate is 25.8 lbs bu-1 with a SED of 2.3 106 -6 -4 -2 0 2 4 6 8 10 12 14 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-18: Test weight study 2004-05 at Plant Breeding Unit, Tallassee. The grain yield of SoilSaver at standard seeding rate is 27.5 lbs bu-1 with a SED of 0.4. 107 -6 -5 -4 -3 -2 -1 0 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-19: Test weight study 2006-07 at Plant Breeding Unit, Tallassee. The grain yield of SoilSaver at standard seeding rate is 25.3 lbs bu-1 with a SED of 1.1. 108 -2 0 2 4 6 8 10 12 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-20: Test weight study 2006-07 at Gulf Coast Research and Extension Center, Fairhope. The grain yield of SoilSaver at standard seeding rate is 18.6 lbs bu-1 with a SED of 2.3. 109 -2 0 2 4 6 8 10 12 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-21: Test weight study 2006-07 at Tennessee Valley Research and Extension Center, Belle Mina.. The grain yield of SoilSaver at standard seeding rate is 24.1 lbs bu-1 with a SED of 0.9. 110 0 1 2 3 4 5 6 7 8 9 10 CIa v 25 20 PI 1 112 61 PI 2 919 91 PI 4 360 80 PI 4 361 03 PI 4 361 04 PI 4 361 05 PI 4 361 10 PI 4 361 14 CIa v 80 89 CIa v 90 07 CIa v 90 11 CIa v 90 12 CIa v 91 10 CIa v 91 12 CIa v 91 16 PI 2 746 08 CIa v 70 10 Soi lSa ver_ 45 Figure 3-22: Test weight study 2006-07 at Wiregrass Research and Extension Center, Headland. The grain yield of SoilSaver at standard seeding rate is 19 lbs bu-1 with a SED of 0.6. 111 IV. ALLELOPATHY OF BLACK OAT (AVENA STRIGOSA SCHREB.) ACCESSIONS Abstract Black oat (Avena strigosa Schreb.) has been considered to have allelopathic potential in suppressing weedy species in the crop field when grown as a cover crop. Various bio-assays have been used by many researchers in screening plant species based on their allelopathic potential. In this study we compared the allelopathic potential of eighteen black oat accessions and SoilSaver using the modified Pederson bio-assay. All the black oat accession and SoilSaver performed better than the control in suppressing radicle elongation of pre-germinated radish (Raphanus sativus L.) seedlings. Accession CIav 2520 expressed the maximum suppression of radicle elongation of the indicator species. . 112 Introduction Black oat has been found to be effective in suppressing different weeds in field condition (Price et al., 2006; Reeves et al., 2005), and this may be due to the release of allelopathic chemicals to the soil. The allelopathic potential of a cover crop can be estimated by in-vitro germination and radicle growth bio-assay of the target species using aqueous leachates collected from the donor species at a standard 1% concentration (Caamal-Maldonado et al., 2001). Earlier researchers used the aqueous leachates from seeds (Cope, 1982), roots (Peters, 1968) or stems on a germination paper to test the germination of the indicator species, but Carlson et al (1983) used the extract agar medium for testing germination. Carlson et al (1983) took only the germination percentage data, which were transformed with arcsine square root transformation in order to equalize among treatment variances. Cope (1982) measured the root length of the leguminous species and shoot length of the grassy species to assess allelopathic potential. According to Pederson (1986) the germination using extract agar is more precise than using germination paper since the germination of indicator species on a germination paper may not be even. He also suggested that root length measurement will give better indication of allelopathic effects than the germination method. But some times the dormancy that varies differently among different seeds is a problem in bio-assay and may result in higher experimental error, but the use of pre-germinated seeds will reduce experimental error (Ben-Hammouda et al., 1995; Wardle et al., 1993; Wu et al., 2001). Even though the germination bio-assay is a good way to test the allelopathic effects of donor plants, some researchers argue that findings of the extract screening bioassay may not be extrapolated to real agronomic situation because the allelopathic interactions may 113 be different in crop fields (Romeo and J.D.Weidenhamer, 1999). But as a preliminary way to select the allelopathic potential of a given species, researchers use germination bio-assay extensively. In this study we used a modified method of Pederson (Pederson, 1986) described by Stoll et al (2006) for the screening of black oat accessions for their allelopathic potential. Materials and Methods Eighteen black oat accessions and SoilSaver were selected based on the results of a previous study of morphology and maturity of black oat (Table 3-1). The entire evaluation for allelopathic potential was repeated three times. Seeds were sown in 7.6 L plastic containers in 1:1 sand and PRO-MIX medium (Sun Gro Horticulture Distribution Inc., Bellevue, WA) at the Auburn University Plant Sciences Research Center (PSRC) greenhouse and watered daily. Thirty seeds were sown and thinned to 15 seedlings per container after emergence. Three replicattes were planted on 1) last week of December, 2006, 2) third week of January and 3) first week of April 2007. Aboveground biomass was harvested by cutting at soil level 5 weeks after planting, shredded into 15 mm pieces and mixed well. From each sample 10 g plant material was soaked in 50 mL of distilled water in opaque plastic containers. Extracts were filtered after 24 hours using coffee filters into another plastic container and 20 ml of filtered extracts were transferred into separate test tubes. As a control we used 20 mL of distilled water instead of filtered plant extract. Agar medium (12g L-1) was prepared by autoclaving the granulated agar (12 g) mixed with distilled water (1 L) at 121? C for 15 minutes. The medium was cooled down to 50 ?C, mixed with the filtered extract in the test tubes, transferred into Petri plates (15 114 x 100mm) and allowed to solidify. Radish seeds (Raphanus sativus L.) pre-germinated for 24 hours with a radicle length < 2 mm were planted at 5 seedlings/ Petri-plate, sealed with parafilm and kept in dark around 22 ?C. The response variable was the radicle lengths 48 h post placement. We calculated the mean radicle length per Petri plate and analyzed the data using a mixed models approach as implemented in SAS Proc Mixed. Treatment (18 accessions and SoilSaver plus untreated control) was the sole fixed effect and run run x trt effects were considered to be random effects. Accession means were compared to either the untreated control or SoilSaver using Dunnett?s test. Result and Discussion Accessions CIav 2520, PI 111261, PI 291991, PI 436103, PI 436104, PI 436105 and PI 436110 have significantly greater radicle suppressive ability of the indicator species than SoilSaver. Accession CIav 2520 showed the most radicle suppressive ability among all accession studied. Even though this screening based on bioassay is an indication of the effectiveness of black oat in suppressing weed growth, in real crop field the interaction of different factors may play their role, influencing the actual expression of the allelopathic potential. Also quantification of the allelopathic chemicals using chromatographic method may give more precise information about the antagonistic chemicals present in these accessions. 115 References Ben-Hammouda, M.R.J. Kremer, H.C. Minor, and M.Sarwar. 1995. A chemical basis for the differential allelopathic potential of sorghum hybrids on wheat. J. Chem. Ecol. 21:775-786. Caamal-Maldonado, J.A., J.J. Jime?nez-Osornio, A. Torres-Barragan, and A.L. Anaya. 2001. The use of allelopathic legume cover and mulch species for weed control in cropping systems. Agron. J. 93:27-36. Carlson, J.R., R.L. Ditterline, J.M. Martin, D.C. Sands, and R.E. Lund. 1983. Alfalfa seed germination in anitibiotic agar containing NaCl. Crop.Sci. 23:882-885. Cope, W.A. 1982. Inhibition of germination and seedling growth of eight forage species by leachates from seeds. Crop Sci. 22:1109-1111. Fay, P.K., and W.B. Duke. 1977. An assessment of allelopathic potential in Avena germplasm. Weed science 25:224-228. Pederson, G.A. 1986. White clover seed germination in agar containing tall fescue leaf extracts. Crop Sci. 26:1248-1249. Peters, E.J. 1968. Toxicity of tall fescue to rape and birdsfoot trefoil seeds and seedlings. Crop Sci. 8:650-653. Price, A.J., D.W. Reeves, and M.G. Patterson. 2006. Evaluation of weed control provided by three winter cereals in conservation-tillage soybean. Renewable Agriculture and Food Systems 21(3):159-164(6). Reeves, D.W., A.J. Price, and M.G. Patterson. 2005. Evaluation of three winter cereals for weed control in conservation-tillage nontransgenic cotton. Weed Technology 19:731-736. 116 Romeo, J.T., and J.D.Weidenhamer. 1999. Bioassay for allelopathy in terrestrial plants, p. 179-211, In K. F. Haynes and J. G. Millar, eds. Methods in chemical ecology. Kluwer Academic Publishing, Boston. Stoll, M.E., A.J. Price, and J.R. Jones. 2006. Cover crop extract effects on radish radicle elongation, p. 184-186 Southern Conservation Systems Conference, Amarillo TX. Wardle, D.A., K.A. Nicholson, and A. Rahman. 1993. Influence of plant age on allelopathic potential of nodding thistle(Carduus nutans L.) against pasture grasses and legumes. Weed research 33:69-78. Wu, H., J. Pratley, D. Lemerle, T. Haig, and M. An. 2001. Screening methods for the evaluation of crop allelopathic potential. Botanical Review 67(3):403-415. 117 Table 4-1: The allelopathic potential of different black oat accessions in comparison to SoilSaver. P > 0 (Dunnett's) Treatment Country of origin Radicle elongation vs. Control vs. SoilSaver ---- mm ---- Control 65.6 PI 274608 Poland 25 <0.0001 1.000 CIav 9116 Canada 23.8 <0.0001 0.962 SoilSaver United States 22.5 <0.0001 CIav 8089 United States 22.2 <0.0001 1.000 CIav 9112 Canada 21.7 <0.0001 0.473 CIav 7010 Brazil 21.3 <0.0001 0.436 PI 436114 Chile 20.6 <0.0001 0.999 CIav 9007 Romania 20 <0.0001 0.472 CIav 9012 Bulgaria 19.4 <0.0001 0.163 CIav 9011 Denmark 19.3 <0.0001 0.394 CIav 9110 Canada 19.3 <0.0001 0.268 PI 436080 Chile 19.1 <0.0001 0.161 PI 111261 Romania 17.3 <0.0001 0.015 PI 436110 Chile 17.1 <0.0001 0.021 PI 291991 Israel 16.8 <0.0001 0.002 PI 436103 Chile 16.1 <0.0001 0.002 PI 436105 Chile 15.3 <0.0001 0.0005 PI 436104 Chile 14.8 <0.0001 <0.0001 CIav 2520 France 14.3 <0.0001 <0.0001 SE 3.7 118 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 CIav 1782 120 5.03 26.67 5.95 2.76 0.24 107.54 4.34 5.33 0.22 29.39 3.49 2004 CIav 1782 138 5.03 69.62 10.24 2.36 0.42 94.37 8.27 5.20 0.41 5.01 4.80 2003 CIav 2520 105 5.03 50.00 5.95 4.40 0.23 132.62 4.34 5.21 0.22 28.59 3.49 2004 CIav 2520 136 5.03 53.00 5.95 3.56 0.26 123.42 4.65 5.60 0.23 9.17 3.49 2003 CIav 2521 120 5.03 48.33 5.95 3.53 0.24 140.69 4.34 6.01 0.22 30.67 3.49 2004 CIav 2521 137 5.03 49.67 5.95 3.24 0.26 123.54 4.65 5.71 0.23 15.20 3.67 2003 CIav 2523 116 5.03 41.67 5.95 3.60 0.42 106.88 8.29 5.32 0.41 25.50 3.49 2004 CIav 2523 141 5.03 47.67 5.95 3.57 0.30 84.86 5.55 4.21 0.28 6.09 4.19 2003 CIav 2524 122 5.03 43.33 5.95 3.64 0.25 133.48 4.48 5.28 0.23 29.22 3.49 2004 CIav 2524 136 5.03 65.47 7.26 2.77 0.38 100.83 7.41 4.50 0.37 13.48 6.36 2003 CIav 2525 120 5.03 45.00 5.95 3.03 0.24 122.40 4.21 5.94 0.21 40.00 3.49 2004 CIav 2525 139 5.03 57.34 7.26 3.25 0.48 105.71 9.53 6.06 0.47 7.31 5.42 2003 PI 78821 120 5.03 53.33 5.95 2.93 0.24 124.81 4.34 6.26 0.22 28.61 3.49 2004 PI 78821 147 5.03 43.33 5.95 4.29 0.27 85.33 5.04 7.18 0.25 5.53 3.58 119 Appendix 1. Year x accession least squares interaction means. . Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 83720 117 5.03 58.33 5.95 4.55 0.27 147.05 5.05 6.06 0.25 32.67 3.49 2004 PI 83720 138 5.03 68.34 7.26 2.96 0.33 91.79 6.28 4.40 0.31 6.63 5.41 2003 PI 83721 120 5.03 65.00 5.95 3.11 0.25 117.29 4.48 5.52 0.23 28.89 3.49 2004 PI 83721 138 5.03 65.67 5.95 3.61 0.31 106.69 5.88 4.93 0.29 11.33 3.49 2003 PI 83723 120 5.03 51.67 5.95 3.90 0.23 112.80 4.09 5.58 0.21 22.56 3.49 2004 PI 83723 141 5.03 53.33 5.95 2.78 0.27 90.55 5.04 5.11 0.26 13.12 3.78 2003 CIav 2894 127 5.03 50.00 5.95 3.70 0.30 98.34 5.55 4.66 0.28 10.89 3.49 2004 CIav 2894 139 5.03 40.05 10.24 2.05 0.35 54.67 6.76 3.50 0.33 2.36 4.80 2003 CIav 2920 120 5.03 41.67 5.95 3.51 0.27 107.44 4.83 4.59 0.24 21.94 3.49 2004 CIav 2920 139 5.03 52.67 5.95 3.49 0.31 92.77 5.88 4.37 0.29 8.06 3.49 2003 CIav 2921 122 5.03 46.67 5.95 4.32 0.25 126.20 4.48 6.15 0.23 23.72 3.49 2004 CIav 2921 140 5.03 53.33 5.95 3.05 0.30 99.25 5.55 5.10 0.28 12.89 3.78 2003 CIav 3214 107 5.03 38.33 5.95 4.41 0.28 106.71 5.28 4.76 0.26 24.33 3.49 2004 CIav 3214 137 5.03 48.67 5.95 3.42 0.24 96.88 4.34 4.28 0.22 12.06 3.49 120 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 111261 103 5.03 65.00 5.95 4.07 0.23 141.46 4.09 4.89 0.21 35.61 3.49 2003 CIav 3372 132 5.03 31.67 5.95 4.38 0.48 109.60 9.53 5.27 0.47 3.44 3.49 2004 CIav 3372 151 5.03 48.33 5.95 3.35 0.80 67.18 16.45 4.14 0.81 2.02 4.37 2003 PI 131695 85 5.03 68.33 5.95 4.45 0.23 127.39 3.98 3.83 0.20 31.00 3.49 2004 PI 131695 127 5.03 60.97 7.26 3.48 0.28 103.32 5.28 4.17 0.26 11.81 4.20 2003 PI 131640 85 5.03 56.67 5.95 4.78 0.23 127.72 3.98 3.67 0.20 25.89 3.49 2004 PI 131640 116 5.03 55.67 5.95 4.30 0.24 103.84 4.21 3.33 0.21 11.72 3.49 2003 PI 131641 86 5.03 58.33 5.95 4.81 0.25 134.30 4.34 3.89 0.22 35.16 3.58 2004 PI 131641 109 5.03 57.33 5.95 4.41 0.24 109.05 4.21 3.62 0.21 20.28 3.49 2003 PI 131642 85 5.03 56.67 5.95 5.00 0.23 107.87 4.09 3.65 0.21 27.22 3.49 2004 PI 131642 113 5.03 40.00 5.95 3.79 0.26 86.50 4.65 3.29 0.23 5.78 3.49 2003 CIav 4639 89 5.03 50.00 5.95 5.28 0.23 132.83 3.98 4.33 0.20 34.67 3.49 2004 CIav 4639 111 5.03 56.67 5.95 5.07 0.24 117.25 4.21 4.25 0.21 20.89 3.49 2003 PI 158244 120 5.03 38.33 5.95 3.20 0.26 122.77 4.65 6.39 0.24 27.83 3.49 121 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2004 PI 158244 139 5.03 65.47 7.26 2.50 0.28 95.61 5.27 4.97 0.26 7.65 4.37 2003 PI 158246 132 5.03 23.33 5.95 5.11 0.48 112.36 9.53 4.65 0.47 2.94 4.20 2004 PI 158246 152 5.03 39.84 7.26 4.14 0.35 90.70 6.78 3.41 0.34 4.60 4.57 2004 PI 274610 140 5.03 54.84 7.26 2.76 0.31 89.83 5.88 4.24 0.29 8.82 5.07 2003 PI 287315 116 5.03 33.33 5.95 3.09 0.24 124.45 4.21 5.12 0.21 35.00 3.49 2004 PI 287315 131 5.03 58.33 5.95 2.93 0.25 112.52 4.48 5.13 0.23 25.65 3.58 2003 PI 291990 91 5.03 56.67 5.95 4.78 0.23 132.89 3.98 4.22 0.20 30.50 3.49 2004 PI 291990 130 5.03 58.00 5.95 4.90 0.27 111.34 5.04 4.34 0.25 16.26 3.67 2003 PI 291991 92 5.03 60.00 5.95 4.60 0.23 125.75 4.09 4.12 0.21 30.94 3.49 2004 PI 291991 119 5.03 61.67 5.95 4.66 0.23 107.99 4.09 3.99 0.21 16.72 3.49 2003 PI 292226 85 5.03 66.67 5.95 4.75 0.24 127.27 4.21 3.63 0.21 32.94 3.49 2004 PI 292226 108 5.03 57.67 5.95 3.87 0.26 97.64 4.65 3.70 0.23 13.73 4.04 2003 PI 304557 120 5.03 46.67 5.95 6.78 0.80 116.17 16.45 5.90 0.81 4.00 3.49 2004 PI 304557 139 5.03 52.33 5.95 4.13 0.25 106.08 4.48 4.16 0.23 7.66 3.78 122 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 436080 102 5.03 33.33 5.95 3.98 0.23 114.68 4.09 4.63 0.21 22.11 3.49 2004 PI 436080 136 5.03 45.33 5.95 3.33 0.24 113.11 4.34 4.18 0.22 19.89 3.58 2003 PI 436082 134 8.71 35.00 5.95 5.01 0.48 74.69 9.53 4.32 0.47 0.61 3.49 2004 PI 436082 136 5.03 48.97 7.26 3.85 0.38 79.96 7.40 3.97 0.37 1.00 5.08 2003 PI 436103 92 5.03 63.33 5.95 4.63 0.24 130.34 4.21 4.31 0.21 28.61 3.49 2003 PI 436104 95 5.03 61.67 5.95 4.97 0.24 122.89 4.34 3.88 0.22 26.56 3.49 2004 PI 436104 111 5.03 56.00 5.95 3.43 0.23 101.44 3.98 3.94 0.20 14.61 3.49 2003 PI 436105 94 5.03 55.00 5.95 4.85 0.24 137.21 4.21 4.75 0.21 35.50 3.49 2004 PI 436105 112 5.03 55.00 5.95 4.68 0.24 112.55 4.21 4.12 0.21 28.46 3.78 2003 PI 436106 91 5.03 53.33 5.95 4.58 0.23 133.46 4.09 4.36 0.21 35.22 3.49 2004 PI 436106 112 5.03 55.33 5.95 4.53 0.23 107.28 4.09 3.70 0.21 22.80 3.58 2003 PI 306419 122 5.03 61.67 5.95 5.06 0.48 120.73 9.53 7.73 0.47 2.28 3.49 2004 PI 306419 151 5.03 73.33 5.95 3.79 0.58 112.55 11.66 6.97 0.57 1.47 4.04 2003 PI 361910 122 5.03 53.33 5.95 4.62 0.48 97.07 9.53 5.06 0.47 6.00 3.49 2004 PI 361910 150 5.03 52.33 5.95 3.83 0.42 140.02 8.29 4.88 0.41 14.89 3.91 123 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 361912 117 5.03 60.00 5.95 5.68 0.48 106.60 9.53 4.61 0.47 5.94 3.49 2004 PI 361912 150 5.03 61.33 5.95 5.10 0.35 86.64 6.78 4.92 0.34 4.42 4.04 2003 PI 401793 134 5.03 23.33 5.95 3.91 0.35 115.32 6.77 7.67 0.33 31.17 3.49 2004 PI 401793 158 5.03 34.67 5.95 3.64 0.58 100.55 11.66 6.47 0.57 6.57 3.67 2003 PI 401794 134 5.03 46.67 5.95 3.43 0.38 102.72 7.40 6.99 0.37 13.85 4.20 2004 PI 401794 163 5.03 43.00 5.95 2.67 0.33 80.09 6.28 5.71 0.31 12.56 4.04 2004 PI 436107 140 5.03 42.33 5.95 4.15 0.24 93.99 4.34 4.06 0.22 11.06 3.49 2003 PI 436108 107 5.03 31.67 5.95 3.60 0.35 91.26 6.78 3.88 0.34 10.72 3.49 2004 PI 436108 136 5.03 49.67 5.95 2.35 0.24 89.83 4.34 4.08 0.22 14.56 3.49 2003 PI 436109 88 5.03 71.67 5.95 4.85 0.24 124.04 4.21 3.69 0.22 27.78 3.49 2004 PI 436109 112 5.03 50.33 5.95 5.64 0.23 111.23 4.09 3.65 0.21 15.28 3.49 2003 PI 436110 92 5.03 60.00 5.95 4.68 0.24 144.09 4.21 4.75 0.21 40.39 3.49 2004 PI 436110 112 5.03 55.33 5.95 5.19 0.25 107.69 4.34 3.88 0.22 26.44 3.49 2003 PI 436111 89 5.03 63.33 5.95 4.61 0.23 112.22 3.98 4.39 0.20 39.78 3.49 2004 PI 436111 116 5.03 56.67 5.95 3.70 0.24 102.52 4.34 3.66 0.22 28.04 3.67 124 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 436112 134 6.16 45.00 5.95 3.80 0.48 106.09 9.53 5.04 0.47 3.48 4.04 2004 PI 436112 161 6.16 52.34 7.26 3.49 0.38 76.78 7.43 4.34 0.37 2.90 4.57 2003 PI 436119 127 5.03 26.67 5.95 4.21 0.33 105.34 6.27 5.30 0.31 11.09 4.20 2004 PI 436119 151 5.03 37.67 5.95 3.85 0.25 87.63 4.48 4.63 0.23 7.39 3.49 2003 PI 436120 125 5.03 48.33 5.95 4.11 0.48 93.60 9.53 3.94 0.47 8.83 3.49 2004 PI 436120 151 5.03 49.33 5.95 3.11 0.28 72.98 5.27 4.59 0.26 11.58 3.67 2003 PI 436121 125 5.03 36.67 5.95 3.99 0.31 97.58 5.88 5.12 0.29 14.00 3.49 2003 PI 436122 127 5.03 26.67 5.95 4.67 0.42 112.36 8.26 5.26 0.41 0.87 4.37 2004 PI 436122 134 5.03 65.00 5.95 3.16 0.30 119.99 5.55 4.20 0.28 17.61 3.91 2003 PI 436124 125 5.03 51.67 5.95 4.10 0.30 109.87 5.55 5.54 0.28 21.11 3.49 2004 PI 436124 147 5.03 48.00 5.95 3.26 0.25 80.38 4.48 4.88 0.23 12.52 3.90 2003 PI 436125 122 5.03 35.00 5.95 4.35 0.42 92.49 8.27 4.43 0.41 8.44 3.49 2004 PI 436125 137 5.03 51.00 5.95 3.73 0.25 99.88 4.48 4.23 0.23 12.58 3.78 2003 PI 436127 120 5.03 53.33 5.95 4.07 0.30 119.93 5.55 5.68 0.28 24.94 3.49 2004 PI 436127 148 5.03 52.33 5.95 3.68 0.28 91.30 5.27 4.60 0.26 13.77 3.58 125 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 436126 131 6.16 35.10 7.26 4.40 0.42 86.13 8.27 4.99 0.41 0.17 3.49 2004 PI 436126 156 5.03 47.00 5.95 3.34 0.35 77.15 6.77 4.14 0.33 2.75 3.91 2003 PI 436130 134 5.03 45.00 5.95 3.58 0.31 96.60 5.88 5.76 0.29 14.17 3.49 2004 PI 436130 149 5.03 56.00 5.95 2.97 0.24 83.86 4.34 5.52 0.22 16.18 3.67 2003 PI 436131 131 6.16 33.33 5.95 3.68 0.48 120.60 9.53 5.61 0.47 9.39 3.49 2004 PI 436131 161 5.03 38.33 5.95 2.74 0.48 65.86 9.53 3.58 0.47 3.95 3.67 2003 PI 436132 122 5.03 45.00 5.95 3.97 0.31 112.04 5.88 5.60 0.29 25.89 3.49 2004 PI 436132 137 5.03 44.33 5.95 2.99 0.31 83.18 5.88 4.20 0.29 9.74 4.80 2004 PI 436133 159 5.03 53.00 5.95 2.96 0.33 67.03 6.29 4.39 0.31 2.92 3.78 2003 PI 436134 127 5.03 35.00 5.95 4.00 0.38 125.96 6.28 4.74 0.31 4.06 3.49 2004 PI 436134 150 5.03 35.67 5.95 2.96 0.30 70.06 4.48 3.78 0.23 5.06 3.58 2003 PI 436113 109 5.03 35.00 5.95 4.52 0.38 94.22 7.41 3.25 0.37 7.33 3.49 2004 PI 436113 139 5.03 49.67 5.95 3.47 0.25 81.49 4.48 3.47 0.23 9.95 3.67 2003 PI 436114 95 5.03 53.33 5.95 4.43 0.23 133.00 3.98 4.22 0.20 37.22 3.49 2004 PI 436114 111 5.03 57.33 5.95 5.29 0.23 105.11 3.98 3.67 0.20 23.72 3.49 126 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 PI 436115 125 5.03 35.00 5.95 4.04 0.38 84.62 7.41 4.07 0.26 3.94 3.49 2004 PI 436115 151 5.03 42.33 5.95 3.51 0.26 72.87 4.65 3.66 0.23 5.55 3.58 2003 PI 436116 114 5.03 31.67 5.95 4.85 0.38 94.80 7.41 3.40 0.37 4.80 3.49 2004 PI 436116 124 5.03 50.33 5.95 3.36 0.27 90.83 4.64 4.06 0.24 8.83 3.58 2003 PI 436117 86 5.03 65.00 5.95 4.96 0.23 127.17 3.98 4.22 0.20 33.28 3.58 2004 PI 436117 112 5.03 55.67 5.95 4.80 0.23 105.87 4.09 3.82 0.21 18.39 3.49 2003 PI 436118 107 5.03 30.00 5.95 4.60 0.31 96.35 5.89 3.73 0.29 18.26 4.20 2004 PI 436118 135 5.03 46.67 5.95 3.40 0.25 84.69 4.48 4.17 0.23 12.61 3.49 2003 CIav 9019 120 5.03 28.33 5.95 4.32 0.27 124.51 5.03 5.49 0.26 19.00 3.49 2003 CIav 9020 89 5.03 51.67 5.95 4.67 0.23 137.61 3.98 4.78 0.20 38.83 3.49 2004 CIav 9020 112 5.03 56.67 5.95 4.57 0.24 111.11 4.21 3.68 0.21 12.78 3.49 2003 CIav 9021 88 5.03 55.00 5.95 4.87 0.23 131.00 3.98 4.33 0.20 43.00 3.49 2004 CIav 9021 128 5.03 61.67 5.95 4.33 0.26 96.35 4.65 3.20 0.23 18.11 3.49 2003 CIav 9022 113 5.03 61.67 5.95 3.55 0.31 132.30 5.89 5.07 0.47 34.33 3.58 2004 CIav 9022 136 5.03 72.00 5.95 2.98 0.24 109.79 4.21 4.42 0.21 23.45 3.67 127 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 CIav 9024 122 5.03 48.33 5.95 3.88 0.24 126.60 4.34 5.53 0.22 28.06 3.49 2004 CIav 9024 141 5.03 67.00 5.95 3.00 0.28 95.71 5.27 5.27 0.26 5.88 3.67 2003 CIav 9030 127 5.03 50.00 5.95 3.34 0.31 96.83 5.88 4.87 0.29 9.44 3.49 2004 CIav 9030 137 5.03 73.33 5.95 4.18 0.27 100.65 4.83 4.56 0.24 18.17 3.49 2003 CIav 8089 92 5.03 61.67 5.95 4.66 0.23 132.11 4.09 4.30 0.21 37.00 3.49 2004 CIav 8089 111 5.03 61.33 5.95 5.49 0.23 111.00 4.09 3.65 0.21 26.17 3.49 2003 CIav 9007 106 5.03 71.67 5.95 4.43 0.23 142.78 3.98 4.72 0.20 41.17 3.49 2004 CIav 9007 132 5.03 68.67 5.95 3.60 0.25 129.49 4.48 4.70 0.23 12.56 3.49 2003 CIav 9011 105 5.03 68.33 5.95 4.20 0.23 140.56 4.09 4.70 0.21 39.89 3.49 2004 CIav 9011 136 5.03 61.00 5.95 3.41 0.27 126.39 4.83 4.91 0.24 14.08 3.58 2004 CIav 9012 135 5.03 70.00 5.95 3.67 0.25 136.44 4.48 5.22 0.23 19.88 3.67 2003 CIav 9014 108 5.03 50.00 5.95 5.30 0.31 122.47 5.88 4.89 0.29 8.11 3.49 2004 CIav 9014 144 5.03 56.67 5.95 4.04 0.30 103.72 5.55 4.51 0.28 9.21 3.67 2003 CIav 9015 25 5.03 73.33 5.95 2.54 0.25 62.19 4.48 2.21 0.23 12.28 3.49 2004 CIav 9015 -32 5.03 65.32 10.24 1.27 0.38 49.88 7.41 2.72 0.37 2.03 5.84 128 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 CIav 9066 131 6.16 31.67 5.95 3.73 0.38 126.85 7.43 4.83 0.37 1.44 3.49 2004 CIav 9066 151 5.03 45.69 7.26 4.38 0.31 90.76 5.88 3.49 0.29 4.60 5.41 2003 CIav 9110 105 5.03 70.00 5.95 4.03 0.24 126.61 4.34 4.81 0.23 33.61 3.49 2004 CIav 9110 137 5.03 66.34 7.26 3.32 0.31 103.88 5.88 4.40 0.29 12.19 4.04 2003 CIav 9112 110 5.03 70.00 5.95 3.35 0.35 116.34 6.80 4.40 0.34 39.33 3.49 2004 CIav 9112 139 5.03 65.00 5.95 2.99 0.27 111.24 4.83 5.07 0.24 12.83 3.49 2003 CIav 9116 105 5.03 73.33 5.95 4.05 0.24 116.33 4.34 4.36 0.23 48.94 3.49 2004 CIav 9116 136 5.03 70.67 5.95 3.59 0.27 125.48 4.83 4.83 0.24 20.89 3.67 2003 PI 274608 103 5.03 58.33 5.95 5.01 0.26 140.47 4.65 4.35 0.23 37.11 3.49 2004 PI 274608 120 5.03 54.67 5.95 4.69 0.23 107.40 4.09 4.05 0.21 18.78 3.49 2003 PI 274609 85 5.03 43.33 5.95 5.14 0.23 108.50 3.98 3.78 0.20 26.28 3.49 2003 CIav 9031 117 5.03 43.33 5.95 4.48 0.38 79.24 7.41 4.44 0.37 4.78 3.49 2004 CIav 9031 143 5.03 65.67 5.95 3.90 0.26 80.75 4.64 4.07 0.23 4.00 3.49 2003 CIav 9035 114 5.03 43.33 5.95 3.28 0.80 84.17 16.45 3.90 0.81 7.06 3.49 2004 CIav 9035 131 5.03 47.00 5.95 4.84 0.25 94.07 4.48 3.57 0.23 10.50 3.49 129 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 CIav 9038 114 5.03 38.33 5.95 5.03 0.58 78.17 11.66 4.40 0.57 2.78 3.49 2004 CIav 9038 152 5.03 47.00 5.95 4.37 0.30 100.13 5.55 4.35 0.28 6.76 4.04 2003 CIav 9043 120 5.03 38.33 5.95 3.99 0.31 130.42 5.89 5.76 0.29 27.39 3.49 2004 CIav 9043 136 5.03 56.47 7.26 3.31 0.28 100.14 5.28 4.94 0.26 9.59 4.57 2003 CIav 9064 65 5.03 53.33 5.95 2.95 0.23 100.95 4.21 3.62 0.21 24.94 3.49 2004 CIav 9064 119 5.03 63.47 7.26 2.70 0.27 88.50 5.27 2.81 0.25 3.98 4.20 2003 PI 158247 86 5.03 66.67 5.95 4.46 0.23 139.89 3.98 3.83 0.20 38.39 3.49 2004 PI 158247 113 5.03 68.67 5.95 5.76 0.24 113.65 4.34 3.19 0.22 13.29 3.67 2003 CIav 5057 109 5.03 28.67 5.95 4.41 0.31 119.54 5.89 4.93 0.29 12.44 3.49 2004 CIav 5057 146 5.03 36.67 5.95 3.47 0.27 93.21 5.03 4.26 0.25 5.92 4.04 2003 CIav 5082 89 5.03 60.00 5.95 4.66 0.23 128.80 4.09 3.94 0.21 34.13 3.58 2004 CIav 5082 115 5.03 54.67 5.95 5.37 0.24 105.31 4.34 3.65 0.22 17.80 3.58 2004 CIav 6858 112 5.03 57.67 5.95 5.58 0.23 106.52 4.09 3.52 0.21 19.21 3.58 2003 PI 186606 85 5.03 53.33 5.95 4.98 0.24 121.40 4.21 4.25 0.21 24.56 3.49 2004 PI 186606 109 5.03 56.00 5.95 5.22 0.23 106.89 3.98 3.67 0.20 19.17 3.49 130 Appendix 1. Year x accession least squares interaction means. Tiller Year NPGS no. Heading SE Angle SE Diameter SE Length SE Node number SE Number SE 2003 CIav 6956 88 5.03 46.67 5.95 4.82 0.23 123.34 4.09 4.30 0.21 26.22 3.49 2004 CIav 6956 112 5.03 54.67 5.95 5.60 0.24 112.93 4.21 3.75 0.21 18.83 3.49 2003 CIav 7010 94 5.03 55.00 5.95 4.79 0.24 127.15 4.21 4.19 0.21 28.97 3.49 2004 CIav 7010 116 5.03 58.33 5.95 3.97 0.26 97.23 4.64 3.46 0.23 18.01 3.67 2003 CIav 7121 120 5.03 43.33 5.95 3.10 0.26 111.90 4.65 5.01 0.23 23.02 3.49 2004 CIav 7121 137 5.03 52.34 7.26 2.82 0.38 105.05 7.41 5.54 0.37 8.27 4.37 2003 CIav 7122 122 5.03 33.33 5.95 3.44 0.24 105.81 4.34 4.28 0.22 22.72 3.49 2004 CIav 7122 139 5.03 54.97 7.26 2.46 0.28 92.78 5.28 3.92 0.26 12.82 4.37 2003 CIav 7280 85 5.03 63.33 5.95 5.12 0.23 126.50 3.98 4.33 0.20 27.78 3.49 2004 CIav 7280 109 5.03 57.67 5.95 4.78 0.23 112.47 4.09 3.87 0.22 20.39 3.49 2003 CIav 8087 105 5.03 38.33 5.95 4.75 0.35 105.21 6.77 4.69 0.33 9.33 3.49 2004 CIav 8087 150 5.03 43.33 5.95 4.58 0.28 103.41 5.27 4.77 0.26 2.34 4.19 2003 SoilSaver 102 5.03 36.67 5.95 4.48 0.25 105.88 4.49 3.89 0.23 14.39 3.49 2004 SoilSaver 112 5.03 48.67 5.95 4.29 0.23 96.64 4.09 4.05 0.21 15.89 3.49 131 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 CIav 1782 29.82 1.14 9.40 0.29 112.94 7.87 0.77 0.06 2.11 2.28 11.00 1.29 2004 CIav 1782 26.54 2.16 9.73 0.57 110.80 15.15 0.90 0.12 -0.14 2.73 6.92 2.87 2003 CIav 2520 33.08 1.14 9.60 0.29 108.60 7.40 0.97 0.06 14.95 2.28 8.85 1.18 2004 CIav 2520 28.09 1.22 9.38 0.31 92.94 8.45 0.69 0.07 0.88 2.28 8.59 1.57 2003 CIav 2521 27.94 1.14 9.53 0.29 83.33 8.14 0.85 0.07 6.81 2.28 10.64 1.25 2004 CIav 2521 25.59 1.22 9.01 0.31 94.34 8.45 0.69 0.07 3.43 2.28 7.32 1.38 2003 CIav 2523 23.86 2.49 8.51 0.57 82.03 15.19 0.64 0.12 7.38 2.28 13.09 1.21 2004 CIav 2523 24.94 1.46 8.55 0.38 109.88 10.12 0.70 0.08 0.46 2.28 11.65 2.22 2003 CIav 2524 31.34 1.18 9.50 0.30 113.24 8.15 0.87 0.07 4.86 2.28 10.46 1.33 2004 CIav 2524 26.39 1.94 9.56 0.51 113.89 13.57 0.75 0.11 1.43 2.73 8.91 2.48 2003 CIav 2525 33.16 1.11 10.25 0.28 110.42 7.63 0.91 0.06 6.73 2.28 10.56 1.21 2004 CIav 2525 27.13 2.49 10.36 0.65 88.33 17.47 0.73 0.14 0.31 2.73 10.23 2.86 2003 PI 78821 29.35 1.14 9.46 0.29 89.47 7.87 0.67 0.06 2.99 2.28 9.61 1.25 2004 PI 78821 31.93 1.32 7.73 0.34 149.73 9.61 1.07 0.08 0.43 2.28 17.12 2.03 132 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 83720 39.47 1.33 10.81 0.34 115.11 9.63 0.93 0.08 5.85 2.28 11.16 1.21 2004 PI 83720 26.09 1.64 9.28 0.43 101.03 11.47 0.59 0.09 0.51 2.73 8.18 2.22 2003 PI 83721 27.80 1.18 9.64 0.30 88.01 8.15 0.82 0.07 4.94 2.28 10.06 1.29 2004 PI 83721 32.14 1.54 8.28 0.40 164.59 10.74 0.86 0.09 1.98 2.28 17.58 1.76 2003 PI 83723 30.44 1.08 9.59 0.28 114.19 7.40 0.92 0.06 2.43 2.28 10.08 1.18 2004 PI 83723 23.96 1.38 8.92 0.34 105.42 9.17 0.75 0.07 1.27 2.28 7.06 1.50 2003 CIav 2894 26.14 1.46 10.22 0.38 97.68 10.12 0.57 0.08 1.49 2.28 6.78 1.50 2004 CIav 2894 15.33 1.77 7.00 0.46 62.50 12.37 0.33 0.10 0.35 2.73 4.83 3.51 2003 CIav 2920 27.68 1.27 9.58 0.33 74.71 8.78 0.46 0.07 2.34 2.28 9.88 1.33 2004 CIav 2920 28.34 1.54 9.12 0.40 94.32 10.74 0.56 0.09 1.03 2.28 10.32 1.76 2003 CIav 2921 31.93 1.18 10.29 0.30 114.47 8.14 0.84 0.07 1.82 2.28 8.73 1.38 2004 CIav 2921 26.94 1.46 8.11 0.38 106.32 10.12 0.76 0.08 2.27 2.28 9.58 1.76 2003 CIav 3214 25.63 1.39 9.39 0.36 75.31 9.63 0.67 0.08 4.65 2.28 9.15 1.18 2004 CIav 3214 21.99 1.14 8.94 0.29 75.34 8.14 0.48 0.07 2.35 2.28 10.24 1.29 133 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 111261 34.43 1.08 9.06 0.28 93.39 7.20 0.92 0.06 19.73 2.28 9.69 1.18 2003 CIav 3372 29.04 2.49 9.99 0.65 122.86 17.47 0.76 0.14 0.61 2.54 10.34 4.95 2004 CIav 3372 17.10 4.29 8.06 1.13 105.36 30.22 0.49 0.23 -0.02 2.33 9.55 4.95 2003 PI 131695 29.50 1.05 8.56 0.27 116.22 7.20 0.71 0.06 21.88 2.28 16.70 1.18 2004 PI 131695 24.86 1.39 7.69 0.36 94.41 9.62 0.59 0.08 1.83 2.73 16.27 1.88 2003 PI 131640 33.39 1.05 8.78 0.27 137.95 7.40 0.90 0.06 17.03 2.28 14.01 1.18 2004 PI 131640 25.29 1.11 8.57 0.28 104.72 8.44 0.62 0.07 1.78 2.28 13.61 1.33 2003 PI 131641 32.60 1.14 8.80 0.29 132.86 7.40 0.86 0.06 24.84 2.33 17.01 1.29 2004 PI 131641 26.98 1.11 8.81 0.28 127.45 7.63 0.98 0.06 1.83 2.28 13.43 1.39 2003 PI 131642 30.61 1.08 9.69 0.28 141.93 7.63 0.69 0.06 11.78 2.28 14.61 1.21 2004 PI 131642 25.09 1.22 9.23 0.31 104.66 8.78 0.65 0.07 0.60 2.28 11.73 1.66 2003 CIav 4639 30.06 1.05 8.83 0.27 90.17 7.20 0.78 0.06 24.34 2.28 16.65 1.21 2004 CIav 4639 28.34 1.11 9.13 0.29 118.34 7.63 0.98 0.06 5.13 2.28 14.89 1.21 2003 PI 158244 33.62 1.22 10.46 0.31 150.77 8.45 0.71 0.07 8.65 2.28 10.84 1.38 134 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2004 PI 158244 25.28 1.38 9.69 0.36 111.77 10.12 0.46 0.08 0.56 2.28 9.40 2.03 2003 PI 158246 34.10 2.49 10.99 0.65 149.11 21.38 0.85 0.17 0.00 2.73 0.00 0.00 2004 PI 158246 27.53 1.77 9.47 0.46 145.47 12.39 0.67 0.10 -0.08 2.73 11.78 2.48 2004 PI 274610 28.16 1.54 10.62 0.40 114.44 10.74 0.68 0.09 0.34 2.28 9.05 2.03 2003 PI 287315 28.23 1.11 9.25 0.28 79.43 7.87 0.62 0.06 5.98 2.28 10.93 1.18 2004 PI 287315 26.35 1.18 9.78 0.30 97.94 8.45 0.48 0.07 3.89 2.28 10.20 1.38 2003 PI 291990 30.56 1.05 8.78 0.27 89.19 7.40 0.82 0.06 13.41 2.28 15.09 1.21 2004 PI 291990 26.41 1.32 8.35 0.34 88.51 9.17 0.67 0.07 2.93 2.28 14.64 1.50 2003 PI 291991 30.20 1.08 8.65 0.28 90.39 7.40 0.67 0.06 14.71 2.28 13.52 1.18 2004 PI 291991 24.08 1.08 8.62 0.28 84.77 7.63 0.61 0.06 3.29 2.28 16.26 1.29 2003 PI 292226 30.85 1.11 8.31 0.28 101.79 8.14 0.65 0.07 26.18 2.28 18.20 1.21 2004 PI 292226 24.21 1.22 7.54 0.31 102.88 8.45 0.65 0.07 1.18 2.28 15.60 1.38 2003 PI 304557 30.65 4.29 11.00 1.13 157.35 30.22 0.76 0.23 0.00 2.28 0.00 0.00 2004 PI 304557 24.69 1.18 7.72 0.30 96.79 8.45 0.58 0.07 0.71 2.28 13.98 1.88 135 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 436080 33.20 1.08 9.41 0.28 88.37 7.40 0.72 0.06 8.65 2.28 10.28 1.18 2004 PI 436080 31.04 1.14 8.53 0.29 109.39 7.87 0.49 0.06 3.83 2.28 12.95 1.33 2003 PI 436082 26.43 2.49 10.66 0.65 109.37 17.47 0.52 0.14 0.03 2.28 3.11 3.50 2004 PI 436082 25.18 1.94 9.19 0.51 111.73 13.54 0.60 0.11 -0.11 2.73 0.24 4.95 2003 PI 436103 30.24 1.11 9.00 0.28 92.74 7.63 0.63 0.06 14.91 2.28 14.18 1.21 2003 PI 436104 30.01 1.14 8.87 0.29 97.10 7.87 0.65 0.06 16.30 2.28 12.98 1.33 2004 PI 436104 23.33 1.05 7.56 0.27 84.17 7.20 0.52 0.06 1.35 2.28 13.89 1.33 2003 PI 436105 30.60 1.11 9.07 0.29 76.23 7.87 0.82 0.06 17.54 2.28 14.15 1.21 2004 PI 436105 25.14 1.11 7.81 0.28 95.39 7.63 0.71 0.06 4.02 2.28 16.39 1.29 2003 PI 436106 30.02 1.08 8.76 0.28 78.86 7.40 0.61 0.06 12.54 2.28 15.99 1.18 2004 PI 436106 23.49 1.08 7.62 0.28 78.57 7.40 0.49 0.06 3.09 2.28 15.86 1.21 2003 PI 306419 38.96 2.49 8.01 0.65 135.14 17.47 0.91 0.14 0.31 2.28 19.42 1.88 2004 PI 306419 39.72 3.04 6.98 0.80 132.87 21.41 1.00 0.17 0.75 2.73 23.54 2.86 2003 PI 361910 23.96 2.49 9.67 0.65 98.81 17.47 0.81 0.14 1.83 2.28 15.71 1.88 2004 PI 361910 37.43 2.17 9.21 0.57 134.28 15.18 0.86 0.12 1.99 2.28 13.70 1.88 136 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 361912 31.71 2.49 7.99 0.65 139.52 17.47 1.52 0.14 4.17 2.28 23.23 1.50 2004 PI 361912 28.64 1.77 6.70 0.46 186.19 12.39 1.21 0.10 0.84 2.28 22.07 2.48 2003 PI 401793 27.95 1.77 9.34 0.46 126.82 12.38 0.39 0.10 0.14 2.28 5.15 2.22 2004 PI 401793 21.22 3.04 7.98 0.80 85.37 21.41 0.30 0.17 0.00 2.28 0.24 4.95 2003 PI 401794 22.49 1.94 8.20 0.51 87.64 13.54 0.34 0.11 -0.25 2.73 4.13 4.95 2004 PI 401794 22.29 1.65 7.72 0.43 80.88 11.48 0.30 0.09 0.08 2.28 3.95 2.48 2004 PI 436107 26.27 1.14 9.26 0.29 95.13 7.87 0.63 0.06 0.60 2.28 11.62 1.66 2003 PI 436108 27.06 1.77 8.16 0.46 88.01 12.39 0.51 0.10 0.99 2.28 7.02 1.44 2004 PI 436108 25.09 1.14 7.67 0.29 77.41 7.87 0.29 0.06 2.05 2.28 13.83 1.44 2003 PI 436109 29.61 1.11 8.63 0.28 92.33 7.63 0.64 0.06 14.41 2.28 15.89 1.25 2004 PI 436109 26.58 1.08 8.63 0.28 112.45 7.40 0.79 0.06 3.70 2.28 15.86 1.29 2003 PI 436110 31.43 1.11 9.25 0.28 92.54 7.87 0.84 0.06 28.38 2.28 15.33 1.18 2004 PI 436110 28.63 1.14 9.21 0.29 120.21 7.87 1.05 0.06 6.38 2.28 15.16 1.21 2003 PI 436111 29.06 1.05 9.18 0.28 90.11 7.20 0.67 0.06 32.95 2.28 15.49 1.29 2004 PI 436111 25.14 1.14 9.06 0.29 85.20 7.87 0.57 0.06 5.62 2.28 12.72 1.25 137 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 436112 27.39 2.49 9.33 0.65 97.51 17.47 0.73 0.14 0.62 2.63 14.36 4.95 2004 PI 436112 23.30 1.94 10.46 0.51 98.16 13.61 0.41 0.11 0.02 2.73 22.93 2.49 2003 PI 436119 30.36 1.64 10.43 0.43 80.25 11.46 0.53 0.09 0.19 2.73 11.13 2.48 2004 PI 436119 23.78 1.18 8.64 0.30 106.19 8.14 0.53 0.07 0.92 2.40 8.87 2.03 2003 PI 436120 34.04 2.49 7.66 0.65 169.11 21.38 1.25 0.17 1.98 2.28 13.71 1.44 2004 PI 436120 29.37 1.38 7.90 0.36 163.83 9.61 0.80 0.08 1.05 2.28 16.49 1.76 2003 PI 436121 33.56 1.54 8.50 0.40 163.03 10.73 0.89 0.09 1.87 2.28 15.09 1.44 2003 PI 436122 28.46 2.16 10.00 0.56 108.97 15.13 0.59 0.12 0.02 2.83 9.47 2.03 2004 PI 436122 25.90 1.46 7.77 0.38 99.67 10.12 0.79 0.08 2.02 2.28 14.49 1.76 2003 PI 436124 25.79 1.46 9.89 0.38 109.06 10.12 0.56 0.08 1.88 2.28 7.21 1.50 2004 PI 436124 22.41 1.18 9.08 0.30 84.48 8.14 0.41 0.07 1.48 2.33 7.87 1.76 2003 PI 436125 28.69 2.16 10.75 0.57 97.23 15.15 0.56 0.12 1.38 2.28 11.04 2.03 2004 PI 436125 26.80 1.18 8.72 0.30 93.19 8.14 0.66 0.07 1.41 2.28 12.77 1.76 2003 PI 436127 30.05 1.46 9.00 0.38 113.18 10.13 0.75 0.08 4.71 2.28 6.77 1.38 2004 PI 436127 23.17 1.38 8.80 0.36 94.68 10.12 0.40 0.08 0.96 2.28 8.62 1.66 138 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 436126 29.53 2.16 11.49 0.57 100.49 15.15 0.47 0.12 0.00 2.28 0.00 0.00 2004 PI 436126 27.52 1.77 9.32 0.46 103.17 12.38 0.49 0.10 0.08 2.28 10.66 3.50 2003 PI 436130 23.67 1.54 7.88 0.40 120.96 10.73 0.79 0.09 0.78 2.28 18.14 1.50 2004 PI 436130 22.47 1.14 7.46 0.29 137.00 7.87 0.73 0.06 1.12 2.33 25.47 1.38 2003 PI 436131 29.04 2.49 9.99 0.65 104.19 17.47 0.56 0.14 0.50 2.28 34.80 2.22 2004 PI 436131 20.86 2.49 6.63 0.65 113.28 21.40 0.61 0.17 0.00 2.28 -0.15 4.95 2003 PI 436132 27.54 1.54 9.50 0.40 112.96 10.73 0.64 0.09 1.48 2.28 7.11 1.44 2004 PI 436132 24.81 1.54 8.60 0.40 87.45 10.74 0.48 0.09 0.02 2.28 9.43 3.50 2004 PI 436133 21.09 1.65 7.99 0.43 114.16 11.49 0.74 0.09 0.00 2.28 -0.09 4.95 2003 PI 436134 31.14 1.64 10.28 0.43 89.16 10.74 0.58 0.09 0.11 2.28 12.36 4.95 2004 PI 436134 21.99 1.18 8.92 0.30 99.26 8.14 0.49 0.07 0.04 2.28 7.85 1.88 2003 PI 436113 27.90 1.94 8.60 0.51 124.60 15.15 0.68 0.12 0.34 2.28 8.04 1.66 2004 PI 436113 24.32 1.18 8.99 0.30 91.94 8.45 0.55 0.07 0.41 2.28 11.08 1.57 2003 PI 436114 29.50 1.05 9.06 0.27 82.24 7.63 0.57 0.06 24.44 2.28 13.65 1.21 2004 PI 436114 24.97 1.05 8.36 0.28 89.59 7.87 0.71 0.06 3.47 2.63 15.55 1.21 139 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 PI 436115 31.78 1.38 8.50 0.36 156.83 13.56 0.86 0.11 0.00 2.28 12.29 4.95 2004 PI 436115 22.71 1.22 9.53 0.31 102.63 8.45 0.61 0.07 0.02 2.28 7.88 2.86 2003 PI 436116 35.19 1.94 8.99 0.51 133.97 13.57 0.97 0.11 -0.63 2.73 8.62 1.88 2004 PI 436116 25.21 1.22 8.77 0.31 101.79 8.44 0.72 0.07 0.45 2.28 12.71 1.66 2003 PI 436117 29.33 1.05 9.11 0.27 94.30 7.63 0.73 0.06 17.02 2.33 15.94 1.18 2004 PI 436117 23.91 1.08 8.37 0.28 102.86 7.40 0.73 0.06 2.85 2.28 15.56 1.44 2003 PI 436118 29.76 1.54 9.87 0.40 128.05 10.75 0.74 0.09 1.59 2.28 8.26 1.33 2004 PI 436118 22.62 1.18 10.08 0.30 84.63 8.15 0.51 0.07 0.78 2.28 11.62 1.44 2003 CIav 9019 25.04 1.32 8.82 0.34 107.42 8.78 0.89 0.07 0.43 2.28 11.28 1.38 2003 CIav 9020 32.44 1.05 8.94 0.27 100.47 7.63 0.67 0.06 28.67 2.28 15.75 1.18 2004 CIav 9020 25.26 1.11 8.25 0.28 92.33 7.87 0.65 0.07 2.29 2.28 14.73 1.44 2003 CIav 9021 30.33 1.05 9.39 0.27 92.33 7.20 0.74 0.06 23.64 2.28 16.20 1.21 2004 CIav 9021 25.15 1.22 7.91 0.31 109.15 9.17 0.81 0.08 4.27 2.28 16.15 1.44 2003 CIav 9022 36.20 2.49 8.35 0.65 98.21 10.75 1.00 0.09 6.86 2.28 9.60 1.25 2004 CIav 9022 26.55 1.11 8.26 0.29 85.83 7.63 0.51 0.06 2.09 2.28 9.49 1.29 140 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 CIav 9024 29.07 1.14 8.93 0.29 74.07 7.87 0.55 0.06 4.06 2.28 11.38 1.25 2004 CIav 9024 24.78 1.38 9.59 0.36 81.88 10.13 0.59 0.08 0.39 2.28 19.76 1.66 2003 CIav 9030 29.81 1.54 6.87 0.40 152.15 10.73 1.13 0.09 1.29 2.28 17.01 1.44 2004 CIav 9030 34.27 1.27 8.82 0.33 183.75 8.79 0.99 0.07 1.53 2.28 21.90 1.76 2003 CIav 8089 29.73 1.08 8.94 0.28 86.67 7.63 0.74 0.06 21.14 2.28 13.89 1.18 2004 CIav 8089 27.43 1.08 8.50 0.28 91.45 7.40 0.85 0.06 6.39 2.28 14.92 1.18 2003 CIav 9007 34.17 1.05 8.89 0.27 99.89 7.20 0.93 0.06 28.23 2.28 10.43 1.18 2004 CIav 9007 29.06 1.18 9.71 0.30 85.05 8.14 0.64 0.07 3.43 2.28 9.98 1.33 2003 CIav 9011 35.95 1.08 8.88 0.28 112.05 7.63 0.97 0.06 27.29 2.33 9.90 1.18 2004 CIav 9011 28.93 1.32 8.83 0.33 93.97 9.17 0.75 0.07 3.22 2.28 9.52 1.38 2004 CIav 9012 31.38 1.18 9.50 0.30 86.48 8.14 0.65 0.07 4.68 2.28 10.56 1.38 2003 CIav 9014 44.13 1.54 8.75 0.40 146.96 9.17 1.42 0.07 3.35 2.28 11.27 1.38 2004 CIav 9014 36.08 1.46 7.76 0.38 200.55 10.13 1.04 0.08 1.35 2.28 18.46 1.66 2003 CIav 9015 18.60 1.18 4.50 0.30 220.04 8.78 0.72 0.07 6.24 2.28 16.86 1.33 2004 CIav 9015 17.70 1.94 3.37 0.51 171.31 17.47 0.51 0.14 0.62 3.77 13.22 4.95 141 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 CIav 9066 36.42 1.94 9.79 0.51 123.07 13.60 1.24 0.11 0.00 2.28 6.79 3.50 2004 CIav 9066 28.80 1.54 10.99 0.43 122.34 10.73 0.51 0.09 0.33 2.84 7.87 3.51 2003 CIav 9110 37.73 1.14 9.13 0.29 113.42 7.40 0.91 0.06 16.48 2.28 9.44 1.21 2004 CIav 9110 31.08 1.54 8.26 0.40 104.20 10.74 0.47 0.09 1.63 2.28 9.07 2.03 2003 CIav 9112 36.65 1.78 8.16 0.46 141.35 12.44 0.95 0.10 12.53 2.28 9.02 1.18 2004 CIav 9112 29.59 1.27 8.16 0.33 125.08 8.78 0.65 0.07 2.21 2.28 12.89 1.57 2003 CIav 9116 35.13 1.14 9.47 0.29 123.33 7.63 0.95 0.06 30.97 2.28 9.51 1.18 2004 CIav 9116 31.79 1.27 9.75 0.33 98.24 8.78 0.58 0.07 4.56 2.28 10.26 1.50 2003 PI 274608 35.52 1.22 10.00 0.31 141.79 8.80 0.99 0.07 31.96 2.28 15.73 1.38 2004 PI 274608 27.64 1.08 9.00 0.28 134.63 7.40 0.87 0.06 2.34 2.28 13.53 1.44 2003 PI 274609 31.06 1.05 10.78 0.27 143.72 7.20 0.68 0.06 13.07 2.28 14.33 1.18 2003 CIav 9031 25.36 1.94 7.99 0.51 128.05 13.57 0.79 0.11 1.81 2.28 19.75 1.66 2004 CIav 9031 26.21 1.22 7.69 0.31 202.48 8.44 0.89 0.07 1.12 2.28 20.75 1.57 2003 CIav 9035 21.65 4.29 10.00 1.13 68.35 30.22 0.46 0.23 0.37 2.28 7.47 1.57 2004 CIav 9035 27.77 1.18 8.43 0.30 125.67 7.87 0.79 0.06 0.76 2.28 12.94 1.58 142 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 CIav 9038 21.15 3.05 11.00 0.80 60.85 21.41 0.46 0.17 0.05 2.28 11.70 2.87 2004 CIav 9038 26.65 1.46 8.34 0.38 85.55 10.12 0.48 0.08 0.12 2.28 11.23 1.88 2003 CIav 9043 32.45 1.54 9.76 0.40 113.99 10.75 0.82 0.09 1.84 2.28 8.57 1.25 2004 CIav 9043 27.50 1.39 8.57 0.36 116.23 9.63 0.74 0.08 0.75 2.73 5.41 1.76 2003 CIav 9064 30.35 1.11 5.56 0.28 126.93 7.87 0.66 0.06 4.99 2.28 12.28 1.25 2004 CIav 9064 24.81 1.32 5.36 0.34 122.33 9.17 0.62 0.07 0.21 2.73 11.02 2.48 2003 PI 158247 28.50 1.05 8.11 0.27 120.74 7.63 0.73 0.06 51.54 2.28 19.60 1.18 2004 PI 158247 27.89 1.11 7.93 0.30 116.02 8.45 1.13 0.07 3.07 2.28 15.87 1.29 2003 CIav 5057 31.30 1.54 10.25 0.40 108.20 10.75 0.69 0.09 1.18 2.28 6.91 1.38 2004 CIav 5057 27.17 1.32 9.09 0.34 87.60 9.17 0.49 0.07 0.20 2.28 14.05 2.22 2003 CIav 5082 30.54 1.08 8.94 0.28 105.07 7.40 0.76 0.06 17.82 2.28 16.33 1.21 2004 CIav 5082 25.81 1.14 8.59 0.29 118.09 8.45 0.78 0.07 2.83 2.28 16.37 1.38 2004 CIav 6858 25.20 1.11 8.37 0.28 91.77 7.63 0.69 0.06 3.30 2.28 16.62 1.29 2003 PI 186606 28.86 1.11 8.87 0.28 85.24 7.63 0.62 0.06 11.86 2.28 14.36 1.21 2004 PI 186606 22.84 1.05 7.65 0.28 87.71 7.63 0.59 0.06 4.79 2.28 16.55 1.29 143 Appendix 1. Year x accession least squares interaction means. Panicle Flag leaf Seed Year NPGS no. Length SE Node number SE Length SE Width SE Yield SE Mass SE 2003 CIav 6956 29.73 1.08 9.06 0.28 94.33 7.20 0.63 0.06 10.19 2.28 16.03 1.29 2004 CIav 6956 26.89 1.11 8.44 0.28 100.58 7.63 0.80 0.06 3.48 2.28 15.58 1.21 2003 CIav 7010 29.85 1.11 9.00 0.28 93.83 7.40 0.64 0.06 12.06 2.28 12.35 1.21 2004 CIav 7010 24.48 1.22 8.08 0.33 104.41 8.44 0.76 0.07 2.04 2.28 14.77 1.38 2003 CIav 7121 32.08 1.22 9.23 0.31 111.72 8.45 0.74 0.07 3.72 2.28 10.96 1.38 2004 CIav 7121 28.17 1.94 9.98 0.51 124.49 13.57 0.68 0.11 0.79 2.73 9.88 2.22 2003 CIav 7122 27.66 1.14 9.60 0.29 80.12 8.14 0.70 0.07 3.28 2.28 9.31 1.25 2004 CIav 7122 25.18 1.39 9.57 0.36 86.61 9.63 0.62 0.08 1.51 2.73 10.07 1.58 2003 CIav 7280 31.39 1.05 9.00 0.27 88.96 7.63 0.61 0.06 13.50 2.28 13.59 1.18 2004 CIav 7280 25.50 1.05 8.44 0.27 108.72 7.20 0.81 0.06 5.22 2.28 15.55 1.18 2003 CIav 8087 25.36 1.77 9.50 0.46 86.75 12.38 0.68 0.10 1.54 2.28 9.54 1.66 2004 CIav 8087 25.48 1.38 9.54 0.38 115.13 9.61 0.73 0.08 0.06 2.28 15.01 2.22 2003 SoilSaver 28.31 1.18 9.33 0.33 117.11 8.15 0.63 0.07 5.02 2.28 9.96 1.29 2004 SoilSaver 25.41 1.08 9.76 0.28 114.52 7.63 0.69 0.06 1.12 2.28 13.28 1.50