2019 ASHS Annual Conference

Grapes are one of the most economically important fruit crops worldwide and are increasingly grown in diverse environments. Grapevine phenology, the seasonal timing of budburst, flowering, and fruit ripening, is a major climate-dependent factor contributing to the local commercial adaptability of grape cultivars. To explore the phenological diversity of wild and cultivated genetic resources in the USDA-ARS Vitis collection in Geneva, NY, USA, date of budburst, bloom, and veraison were recorded for 1,573 accessions from 2011 to 2013. Additional historic phenological data was retrieved from the Germplasm Resources Information Network (GRIN-Global). Growing degree days (GDD) from base 10 ℃ were calculated from day 60. Budburst values ranged from 15.1 to 128.6 with an average of 62.9 GDD, bloom date ranged from 171.3 to 1029.6 with an average of 337.1 GDD, and veraison ranged from 823.5 to 1571.8 with an average of 1172.9 GDD. Seasonal correlations were high for bloom and veraison (0.86 to 0.95) and moderate for budburst (0.60 to 0.66). Phenological classification for grapevine genetic resources will help promote their utilization for research and targeted breeding of adapted cultivars.