Secondary Bud Growth and Fruitfulness of Vitis Vinifera L. ‘Grenache’ Grafted to Three Different Rootstocks and Grown within the Texas High Plains AVA

ABSTRACT In recent years, the economic impact of the grape and wine industry within Texas has significantly increased. The majority of grapes grown in Texas are produced within the Texas High Plains American Viticultural Area (AVA). Vineyards within this AVA are subject to late spring frosts that may potentially reduce crop yields, and lower fruit quality. Objectives of this experiment were to compare the growth and fruitfulness of shoots grown from primary and secondary buds of V. vinifera ‘Grenache’ vines grafted onto three rootstocks (110 R, 1103P, and Freedom). Over two growing seasons, field-grown vines were exposed to the following treatments: primary bud growth and forced secondary bud growth (simulated late spring frost). Leaf gas exchange, pruning cane weight, vine yield, and fruit maturity data were collected each year. Bud treatment or rootstock did not influence leaf gas exchange. Cane weight and yield data were greater for shoots grown from primary bud shoots, and rootstock 1103P. In addition, berries grown from primary buds and 1103P rootstocks were more mature compared to fruits from secondary buds or vines grown on other rootstocks. Results offer insight into the potential interaction of ‘Grenache’ scions with grafted rootstocks during a late spring frost within the Texas High Plains AVA.