Exploring New Technologies for Sustainable Viticulture in the Southeastern United States
Type of DegreeMaster's Thesis
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In the southeastern United States, Pierce’s Disease (PD) is the major limiting factor for production of Vitis vinifera L, European wine grapes. Recently bred, PD resistant 87.5% V. vinifera selections (‘U0501-12’, ‘U0502-01’, and ‘U0502-10’) from the UC Davis breeding program were planted at the Chilton Research Extension Center (CREC), Clanton, AL in 2010. A two-year study of the phenological development and viticultural characteristics was carried out during 2015 and 2016 in order to characterize V. vinifera in the high PD pressure environment of central Alabama. Results for dormant pruning weights indicate that all three selections grew vigorously based on estimated dormant pruning cane weight. ‘U0501-12’ produced the highest pruning weight (2.9 kg/vine), and the two remaining selections each exceeded 2.4 kg/vine in 2016. During 2015, all selections yielded between 8.7 kg/vine for ‘U0501-12’ and 10.9 kg/vine for ‘U0502-10’. Through the 2016 season, ‘U0502-10’ was the most productive selection, yielding 13.4 kg/vine. ‘U0502-10’ also had the largest clusters, averaging between 467.4 g and 567.7 g. Based on the results of the first study, the vigor and productivity of V. vinifera grapevines in the Southeast hold great promise as a new technology for sustainable viticulture production in Alabama and the Southeast. To complement the growing viticulture industry of Alabama and the Southeast, a rootstock study of commercially available scion and rootstock combinations was planted at the CREC in 2014. The second experiment consisted of the following treatments: ‘Norton’ own-rooted (OWR), ‘Norton’ grafted on ‘Paulsen ‘1103’ (‘1103P’), grafted on ‘Kober 5BB’ (‘5BB’), and on ‘Teleki 5C’ (‘5C’), as well as scion cultivar ‘Chardonel’ OWR and ‘Chardonel’ grafted on ‘1103P.’ Evaluations were conducted throughout the 2015 and 2016 growing seasons to determine the effect of rootstocks on phenological development, vegetative growth, and fruit quality characteristics of hybrid bunch grapes grown in central Alabama. Results indicate that during the first year of crop production, ‘Chardonel’ grafted on ‘1103P’ yielded 8.3 kg/vine. ‘Chardonel’ OWR and ‘Chardonel’ on ‘1103P’ were the best performing combinations in terms of cropping potential. Rootstock suckering was notable for ‘Chardonel’ grafted on ‘1103P’ where vines produced an average of 8 rootstock suckers per vine throughout the growing season, while no other combination exceed one rootstock sucker per vine throughout the year. Trunk cross-sectional-area (TCSA) indicated the treatments with the highest vigor at the end of the 2016 growing season were ‘Chardonel’ grafted on ‘1103P’ and ‘Chardonel’ OWR, while ‘Norton’ grafted on ‘5BB’ resulted in the lowest vigor of only 19.0 cm2 TCSA. Continued research is needed with new V. vinifera selections, rootstocks, crop load, and canopy management techniques to enhance quality and sustainability of Alabama’s viticulture industry.