Effects of growth retardant application on grape quality of « Mavrodafni » grapevine variety

Abstract

The effects of bloom applications of 2-Chloroethyltrimethylammonium chloride (CCC) and Succinic acid-2,2-dimethylhydrazide (SADH) on fruit quality of Mavrodafni wine grape variety were studied. Over the vegetative period of 2000, sprays of 500 or 1 000 mg/l CCC and 3 000 or 6 000 mg/l SADH were applied, two weeks before bloom or at 20 p. cent of bloom in a completely randomized experimental design, replicated 10 times. Bunch and berry characteristics, berry composition, and phenolic maturity were measured at harvest. There were no differences between the two days of application. Berry number per bunch and per cm of rachis length, were increased by CCC 1 000 mg/l and SADH 6 000 mg/l treatments. Berry weight was decreased by all treatments with a greater reduction in CCC 1 000 mg/l treatment. Soluble solids were reduced by SADH treatment with a greater reduction in 6 000 mg/l of SADH and increased by CCC treatments at both concentrations. Anthocyanin concentration and extractability were increased in CCC at 1 000 mg/l treatments, while the extractability of grains tannins was reduced. A strong decrease of bud fertility was observed in 6 000 mg/l of SADH.