Yield, Resistance and Fiber Quality Performance of Reniform Nematode resistant QTL Ren barb2 in BARBREN-713 Derived Upland Cotton Lines
Type of DegreeMaster's Thesis
Agronomy and Soils
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Reniform nematode (Rotylenchulus reniformis Linford and Oliveria) is a major pest of upland cotton (Gossypium hirsutum L.) in Alabama. BARBREN-713 is a germplasm with high resistance to reniform nematode (RR) released by combined effort of Texas A&M and USDA- ARS. The quantitative trait locus (QTL) named Ren barb2 was identified as closely linked to genes that contribute the most resistance. An interest has grown to test the real world performance of resistance genes associated with this QTL in terms of both yield and fiber quality in field studies. A population numbered 148 was developed at Auburn University by crossing BARBREN-713 with an elite breeding line AU3202. This population was tested with gel based electrophoresis and two groups were selected based on the presence or absence of Ren barb2 , with each group containing 20 lines. In spring of 2014, several greenhouse screening tests were conducted and nematode egg count data was obtained to determine RR resistance. Field testing was done at Tennessee Valley Research and Extension Center (TVREC) in Belle Mina, Alabama in two locations: one field infested with RR and one field not infested. Yield, nematode egg count, and fiber quality data were obtained. Data showed that the QTL Ren barb2 did contribute majorly to resistance to RR even in a different genetic background, and yield of those lines homozygous positive for the marker were 22% higher in a heavily RR infested field. However, a slight reduction in yield potential was observed in the nematode-free field, and no significant effect on fiber quality was observed.