TY - JOUR T1 - Response of 'Perlette' Grape Berries to Gibberellic Acid Applied during Bloom or at Fruit Set JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 19 LP - 23 DO - 10.5344/ajev.1971.22.1.19 VL - 22 IS - 1 AU - A. N. Kasimatis AU - R. J. Weaver AU - R. M. Pool AU - D. D. Halsey Y1 - 1971/01/01 UR - http://www.ajevonline.org/content/22/1/19.abstract N2 - The response of the 'Perlette' grape variety to gibberellic acid applied during the bloom or fruitset stage was studied in commercial vineyard trials in the Coachella and San Joaquin Valleys and at the University of California, Davis. Applications of 10 ppm during bloom in the commercial vineyards and 15 ppm at Davis effected thinning in only 3 of 5 trials in 1968. Berry size response to fruit-set sprays at concentrations of 40-80 ppm was significant in all trials, however. In 1969, concentrations of 2.5 and 10 ppm during bloom were ineffective in loosening the clusters in a Coachella trial, although significant response in berry size, increase resulted from fruitset applications of 50 and 80 ppm gibberellic acid in 2 additional tests. ER -