GIRDLING, AUXINS AND CYTOCHININS ON FRUIT QUALITY AND EARLINESS OF HARVEST IN PEACH CV. DIAMOND IN THE ÁREA OF THE DEPRESSÃO CENTRAL- RS

Abstract

With the objective to anticipate the harvest period and to enhance fruit size in peach c v. Diamante, in the two auxins: acid (3.5.6-TPA) and 2,4-diclorofenoxipropionic acid (2.4—DP), a citocinine (pheni I urea) and girdling of the main branches werc applied on trees located in the Depressão Central of Rio Grande do Sul, at the Estação Experimental of the Federal University of Rio Grande do Sul, in Eldorado do Sul, latitude 30°39'S and longitude of 5I °06'W. The following treatments were applied at phase II of fruit development, in a randomized block design: 1) 10 ppm 3,5,6 TPA; 2)20 ppm 3.5,6 TPA; 3) 10 ppm 3.5,6 TPA plus girdling of branches; 4) 20 ppm 3,5,6 TPA plus girdl ing of branches; 5)25 ppm 2,4 -DP; 6)50 pppm 2,4-DP; 7)25 ppm 2.4-DP plus girdling of branches; 8)50 ppm 2,4-DP plus girdling of branches; 9) 10 ppm pheni turca (CPPU); 10) girdling of branches; and II) control. ALI the chemicals were applied directly to the fruits, spending about 1,25 lítree. Fruit diameter, of 10 fruits per troe, was measured weekly, from thinning to harvest. The number of fruits and total prodution per tree was determined. The percentage from the total number of fruits at each harvest was determined at the end of the harvesting period. Aux i n treatments and girdling of branches did not increase total number of fruits/tree and did not increase average fruit weight. However, auxin treatment, specially 20 ppm 3,5,6- TPA with or without girdling of branches, resulted in anticipation of about 15 days in begining of harvest. Fruit quality was not affected by any of the treatments.