Exploring the Growth and Cropping Potential of Pierce’s Disease Resistant Vitis ViniferaL. Selections for Enhanced Viticultural Sustainability in Alabama and the Southeast

Abstract

Cultivation of Vitis viniferaL. grapevines has not been economically feasible in the southeastern U.S. due to the major limiting factor, Pierce’s disease (PD), caused by the endemic, xylem-limited bacterium Xylella fastidiosa.Heretofore, hybrids of V. viniferax V. arizonica/candicanshave not been evaluated in the hot and humid subtropical climate of central Alabama. In 2010, an experimental vineyard consisting of three UC Davis developed PD resistant 87.5% V. viniferaselections (‘U0501-12’, ‘U0502-10’, and ‘U0501-12’) was planted at the Chilton Research and Extension Center, (CREC), Clanton, AL for the purpose of investigating the survival rate and overall performance of these selections in the southeastern U.S. Preliminary studies in our lab suggest the V. viniferaselections responded well to local conditions and were free of PD infection. This report focuses on recent two-year assessment of vegetative growth, cropping potential, and fruit quality of V. viniferaadvanced selections during the period of vine establishment. Our results suggest ‘U0501-12’ had the smallest trunk cross-sectional-area in both years. Pruning weights for all selections ranged between 1.7 and 2.0 kg/vine in both study years. Total yield in 2015 was 8.7, 10.7 and 10.9 kg/vine for ‘U0501-12’, ‘U0502-01’, and ‘U0502-10’, respectively. Furthermore, ‘U0502-10’ consistently had the largest cluster size and lowest cluster number per vine. The PD resistant V. viniferaselections demonstrated high cropping potential and plant vigor in both study years, indicating they can sustain viticulture in the southeast while enhancing opportunities for the grape growing industry in the region. Further work to thoroughly characterize the viticultural performance of PD resistant V. viniferaselections in Alabama’s environment is critical.