Effect of plant bioregulators on the promotion of flowering in mango cv. Dusehri

Abstract

The effects of NAA (100 or 200 ppm), Cycocel [chlormequat] (CCC; 500 or 1000 ppm), TIBA (100 or 200 ppm) and paclobutrazol (5 or 10 g a.i. per tree) on the flowering of 25-year-old mango (cv. Dusehri) trees were studied in Gangian, Hoshiarpur, Punjab, India, during 1999/2000. The growth regulators were sprayed to trees in the morning except paclobutrazol, which was applied as a soil drench. Panicle emergence was earlier by 2-8 days in treated trees. The growth regulators, particularly paclobutrazol, advanced the flowering time from 4 February to 27 January. Paclobutrazol reduced shoot and internode lengths compared to the control. TIBA and CCC also reduced the vegetative growth relative to NAA. Paclobutrazol was more effective than CCC in controlling the vegetative growth. The panicle length was reduced with increasing rate of the growth regulators except NAA, for which the opposite trend was recorded. The trees treated with paclobutrazol showed the lowest levels of floral malformation (1.50 and 1.30% at 5 nd 10 g a.i. per tree, respectively). The ratio of male to hermaphrodite flowers was lower with paclobutrazol at 5 (1.42) and 10 g a.i. per tree (1.22), and NAA at 100 (1.70) and 200 ppm (1.50). TIBA and CCC were on a par with the control with regard to this parameter.