This work is a continuation of studies conducted in the San Joaquin Valley toward determining the most effective canopy management practices for fruit composition, quality, and yield while being cost-efficient and adaptable to mechanization. Previous work was conducted on training system and trellis designs and the effects of fruit exposure on yield and fruit composition. The current study compares pruning systems which can be mechanized and are much different in crop level, vegetative development, and canopy configuration. Six systems involving bilateral and quadrilateral cordon training and hand, machine-hedge, and minimal pruning are being compared with French Colombard and Barbera. 1994 was the second year of a 3-year study. The treatments include: bilateral (Bilat) and quadrilateral (Quad) cordon training under both hand (Hand) and machine (Mach) pruning; and minimal pruning (Minimal Pruning/Cordon Training = MPCT) is also being compared with and without hedging to adjust crop load after fruit set. Generally, the treatments with the lowest pruning severity (MPCT, followed by MPCT-Adjust, Quad Mach, Bilat Mach, Quad Hand, and Bilat Hand) produced the most clusters of least weight. Thus, the vines tended to adjust crop loads with smaller clusters and berries. This resulted in comparable yields from all treatments except for lower fruit weights from the bilateral cordon pruning treatments and MPCT Adj. in French Colombard and the hand pruning treatments in Barbera. Thus, the most restrictive pruning level (hand) and vine canopy training (bilateral cordon) systems still tend to be the most limiting to yield and without any improvements in fruit maturation and composition. Fruit composition was not affected in French Colombard except for a 2-week or more delay in harvest from MPCT. The bilateral cordon systems, whether hand or machine pruned, have been restrictive in overall yield potential while there was no advantage in the MPCT over machine pruning. Adjusting crop load after fruit set in MPCT has not responded favorably; it reduces yield while not improving fruit composition. Overall, this second year of data indicates the greatest advantages with quadrilateral cordon training in this vigorous cultivar, especially with machine pruning. Barbera is responding favorably to machine pruning in the-second year of treatment by producing maximum yields with comparable fruit composition to the hand-pruned systems. Overall, the two machine pruning treatments « Bilat. Mach and Quad Mach ~ produced the highest yields with favorable fruit composition. MPCT pruning showed no improved yields over machine pruning and ripened later with lower berry skin anthocyanin. Additionally, MPCT Adj did not show any benefits from crop load adjustment after fruit set. The hand-pruned systems produced a trade-off, ie. higher anthocyanin in Quad Hand but higher bunch rot in Bilat Hand. To date, quadrilateral cordon training with machine pruning is most favorable for French Colombard. Barbera showed some delay in fruit maturation from machine pruning in the first year; machine pruning is now producing maximum yields without delayed ripening. The MPCT treatments have been disappointing. While they may reduce or eliminate pruning costs, fruit ripening is delayed by two weeks or more and with lower fruit anthocyanin (Barbera). Adjusting crop load in MPCT after fruit set is not producing favorable crop thinning effects. This is not surprising, as the supportive shoots and leaf canopy are removed with the clusters.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1994-11-22 17:39:142017-11-22 17:39:55Wine Grape Canopy Management Practices in the San Joaquin Valley