Effect of Succinic Acid-2,2-Dimethylhydrazide and (2-Chloroethyl) Trimethylammonium Chloride on Shoot Growth of 'Tokay' Grapes

Abstract

The plant-growth retardants CCC [(2-chloroethyl) trimethylammonium chloride] and Alar (succinic acid-2,2-dimethylhydrazide), in concentrations of 1,000 to 6,000 ppm, retarded elongation of young 'Tokay' shoots, with CCC the more effective. Both compounds inhibited the length of young internodes more than that of older internodes. Alar at 1,000 ppm induced some growth stimulation of young internodes until 14 to 20 days after treatment. CCC at higher concentrations slowed leaf growth, whereas Alar usually stimulated it. When a solution containing potassium gibberellate (KGA₃) at 100 ppm and CCC at various concentrations was applied to the shoots, the KGA₃ completely overcame the CCC-induced inhibition. Applications of KGA₃ could not fully overcome the inhibition of shoot growth induced by Alar at concentrations of 2,000 ppm or higher.