Trellises for Wine Grape Canopy Management in the San Joaquin Valley

A wine grape trellis trial was designed and planted in 1986 at the U.C. Kearney Agricultural’ Center in the San Joaquin Valley. The purpose was to determine the most suitable trellis system for optimum fruit production and composition in cultivars of major importance to the area; ease and economics of vine management and mechanization were also considerations. Two cultivars, French Colombard and Barbera, were tested on 8 trellis designs suited to mechanization over 3 years, 1989-91. Data collection involved measurements of vine growth and light environment and fruit characteristics and composition; wine making, must and wine composition, and wine sensory analysis were also performed. Contrast analysis was conducted on major comparisons of vine training and trellis configuration for individual years and all 3 years (overall effects). The addition of one foliage support wire above bilateral cordons (11″ distance) increased pruning brush weights; vine yield was also increased through increased berry and cluster weights and with little or no effect on fruit composition in both cultivars. Similar effects were also obtained by increasing the bilateral cordon height by 11″ in both cultivars and with some advanced fruit maturation in Barbera.