RT Journal Article SR Electronic T1 Effect of Ethephon and Gibberellin on Maturation of Ungirdled Thompson Seedless Grapes JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 11 OP 13 DO 10.5344/ajev.1979.30.1.11 VO 30 IS 1 A1 Ghazi I. El-Banna A1 Robert J. Weaver YR 1979 UL http://www.ajevonline.org/content/30/1/11.abstract AB Thompson Seedless grapevines were sprayed with either ethephon at 100, 250, and 500 ppm at véraison or with KGA3 at 5, 25, and 50 ppm one week after fruit-set. All fruits were harvested at about 19°Brix. Ethephon-treated grapes matured 16 days earlier than did the controls, and KGA3 retarded maturation 32 days beyond that of the non-treated vines. Thus the harvesting period for this cultivar was extended by about 48 days.Ethephon application had no effect on yield, cluster weight, berry weight, or size. However, KGA3 produced increases in the above-mentioned parameters. A high juice percent resulted from the application of these compounds, but ethephon treatments gave the higher values. Moreover, higher values in the °Brix/ acid ratio, and lower ones in acidity, were caused by ethephon. GA3 increased acidity, but decreased the °Brix/acid ratio.