Fruit development of Carina (Shiraz × Sultana) in response to growth regulators applied at calyptra dehiscence

Abstract

Growth regulators known to improve yield and quality of Zante and a mechanical treatment utilizing high velocity air and a high pressure water spray to physically dislodge the calyptras were applied at dehiscence in 1979 and 1980 to vines of Carina, a male-sterile hybrid selection of Shiraz x Sultana. The vines were grown in the Barossa Valley, South Australia. The mechanical treatment was ineffective in dislodging the calyptras and there were no significant differences in yield or components of yield between treated and untreated vines in either year. The three growth regulators, CCC 100 ppm + GA 1 ppm, 4-CPA 20 ppm + GA 0.5 ppm, and GA 10 ppm, had marked effects on yield and components of yield, but the response varied between sprays and between years. In 1980 4-CPA + GA produced more berries per bunch, heavier bunches and more fresh fruit per vine than both CCC + GA and GA, while in I98 1, 4-CPA + GA and GA were superior to CCC + GA. There were no differences in concentration of soluble solids, pruning weight or dried berry weight in either year. The processed dried fruit of all treatments was of excellent quality.