2018 ASHS Annual Conference

In 2017, there were approximately 1,767 grape bearing hectares, and 394 wineries in the state of Texas. Within the state, the grape and wine industry had an overall economic impact of $13.1 billion. The vast majority of producing vineyards in Texas are located in regions which are subject to late spring frosts (which can severely reduce crop yield). Primary grape (Vitis vinifera) buds are considered less hardy, but more fruitful when compared to secondary buds. If Texas growers were more informed regarding grape cultivar secondary bud fruitfulness, secondary bud fruitfulness could possibly influence cultivar selection during vineyard planning. Therefore, objectives of this two growing season experiment were to compare growth and fruitfulness of shoots grown from primary and secondary buds of two V. vinifera cultivars on the Texas High Plains. V. vinifera ‘Cabernet Sauvignon’ and ‘Grenache’ vines on 110R rootstocks (trained to vertical shoot positioning with 2 cordons, 4 spurs / cordon, and 2 buds / spur), and planted in a randomized complete block design in 2006 were used for the experiment. Year one treatments included: primary bud remained (P), and following bud break (5 to 15 cm of new growth) primary buds removed (S). Year two treatments for ‘Grenache’ were repeated as in year one (PP, primary year one and year two, and SS, secondary year one and year two). Growing season two treatments for ‘Cabernet Sauvignon’ included PP, primary bud year one, and secondary bud year two (PS), secondary bud year one, and primary bud year two (SP), and SS. Pruning weights, gas exchange data, and fruit quality data were collected each growing season. For each cultivar, pruning data indicate P, or PP shoots had greatest vegetative growth. Gas exchange, soluble solids (ºbrix), and mean berry weight data indicate few differences between treatments. However, PP ‘Cabernet Sauvignon’ and ‘Grenache’ vines had greatest cluster weights. For ‘Grenache’ vines, yield was reduce 30% in SS vines. In addition, compared to PP vines, yield of ‘Cabernet Sauvignon’ vines was reduced 45, 55, and 66% for PS, SS, and SP vines, respectively. Future research will look to determine additional cultivar differences, vine maturity response, and economic assessments.