EFFECT OF SOME GIBBERELLIC ACID AND FORCHLORFNURON APPLICATION ON PRODUCTIVITY AND BERRIES DEVELOPMENT OF EARLY SWEET GRAPES

Abstract

This study was conducted during the two consecutive seasons of (2016 and 2017) in a private vineyard located at El-Sadat City, Menoufia Governorate, to study the effect of gibberellic acid (GA3) and forchlorfnuron (CPPU) application on productivity and berries development of Early Sweet grape cultivar. The vines were five years old, spaced at 2×3 meters apart, grown in a sandy soil and trellised according to the Spanish Parron system. Eight treatments were applied by using dipping clusters with CPPU at concentrations from 1 to 7ppm after fruit set directly in combined plus spraying with GA3 at 20 ppm at 6-8mm berry diameter in additionally control treatment. The results revealed that all CPPU and GA3 applications had the best results in comparison with control in both seasons. Excessive CPPU doses + spraying clusters with GA3 increases yield and physical properties of berries i.e. berry weight, size and firmness, but it delay maturation. In contrast, lower CPPU doses + spraying clusters with GA3 cause a slightly in retarding maturation but reduces yield and its components. On the other hand, moderate CPPU doses (dipping clusters with CPPU at 5ppm + spraying clusters with GA3 at 20 ppm) had an achieving in appropriate balance between yield and cluster quality attributes of Early Sweet grapevines in both seasons.