Pierre Helwi,* Justin Scheiner, Andreea Botezatu, Aaron Essary, and Daniel Hillin
*Texas A&M AgriLife, Texas A&M AgriLife Research and Extension Center, 1102 E. Drew, Lubbock, TX 79403 (pierre.helwi@ag.tamu.edu)

Crop load is a common measure of yield relative to the size of the producing grape- vine and can be managed by viticulture practices such as pruning and shoot- and fruit-thinning. In this project, the crop load of Tempranillo vines from the Texas High Plains AVA was manipulated using three practices to reflect three different crop load levels: vines pruned to two buds per spur (2B), vines pruned to three buds per spur (3B), and vines pruned to three buds per spur and fruit-thinned using a mechanical harvester at 30 days post-bloom (3BFT). Berry chemistry was monitored during the season, and clusters were harvested when the most advanced treatment reached the desired ripening level. Yield at harvest was lowest for the 3BFT treatment that reflected the lowest crop load, followed by 2B and then 3B. 3BFT treatment had the fastest rate of ripening compared to the two other treatments, with higher soluble
solids, sugar content, pH, and tartaric acid at harvest. Wines from this treatment were characterized by higher alcohol, pH, more tartaric and malic acids, greater titratable acidity, and were of deeper color. This study shows that crop load, which has a strong influence on berry chemistry at harvest and wine quality, can be adjusted by the level of pruning and/or by fruit-thinning using a mechanical harvester at 30-days post- bloom.

Funding Support: Texas Department of Agriculture