TY - JOUR T1 - Effect of Root Temperature on Budbreak, Shoot Growth, and Fruit-Set of 'Cabernet Sauvignon' Grapevines JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 82 LP - 89 DO - 10.5344/ajev.1975.26.2.82 VL - 26 IS - 2 AU - W. M. Kliewer Y1 - 1975/01/01 UR - http://www.ajevonline.org/content/26/2/82.abstract N2 - Three-year-old dormant 'Cabernet Sauvignon' vines, growing in 5-gallon containers in a greenhouse, were pruned to two 10-node canes and then grown for 9 weeks in water baths With root temperatures kept at 11, 15, 20, 25, 30, and 35 C. Air temperatures were the same for all treatments, fluctuating between a minimum of 20 C at night and a maximum of 32 C in the day.Budbreak and bloom occurred 3 to 8 days earlier at 25-30 C than at 11 C. The number of buds that broke per vine increased with temperature, and was 2 to 3 times as great at 30-35 C as at 11-15 C. Total shoot growth per vine, measured as length or dry weight, was maximal at 30 C root temperature, as was also the total number of leaves and leaf area per vine. Average shoot length, dry weight per unit length of stem, leaf area, and leaf and cluster dry weights were significantly less at 35 C than at lower root temperatures. With an increase in temperature between 15 and 35 C, there was a decrease in percent dry matter in stems but an increase in leaves. The number of cluster per vine was proportional to the number of buds that broke. The number of berries set per vine did not differ significantly with temperature. However, the number of berries per cluster was significantly greater at 11 C than at root temperatures of 20 C or higher, with berry set approximately proportional to leaf area per cluster. ER -