Effect of Growth Regulators on Phalsa (Grewia Asiatica. L.) I. Growth and Fruiting

The present investigation on the effect of plant regulators on growth and fruiting of phalsa has brought out that GA treatments except in combination with 2,4-D and PCPA increased the vegetative growth significantly and 2,4-D, PCPA and OCLPA 80 ppm reduced it considerably. The treatments which reduced vegetative growth also showed epinastic effect on leaves and there by had considerable effect on yield. In general all the treatments reduced the number of flowers per branch and the percentage of fruit set. However, the effect on fruit drop was most marked and maximum reduction was obtained in GA 60 ppm followed by 2,4,5-T 5 ppm and GA 60 ppm plus urea one per cent. GA treatments were effective in giving early maturity. GA 60 ppm plus urea one per cent, NAA (50 and 75 ppm) and OCLPA 80 ppm reduced the duration of harvesting, GA 60 ppm plus 2,4-D 2.5 ppm and 2,4 D 2.5 ppm increased it and PCPA delayed the start of harvesting.

Application of plant regulators increased the yield of phalsa greatly and the most effective treatment was GA 60 ppm plus 2,4,5-T 5 ppm. Next came 2,4-D 2.S ppm. Other favourable treatments were OCLPA 40 ppm, GA 60 ppm plus 2,4-D 2.5 ppm, NAA 50 ppm GA 60 ppm followed by 2,4,5-TP 5 ppm and PCPA 40 and GA 60 ppm plus urea one per cent. PCPA 40 ppm only considerably reduced the yield. The effect on yield is mainly due to their effect on fruit size and fruit drop. Accordingly maximum weight and volume of fruit was obtained in GA 60 ppm plus 2,4,5-T 5 ppm followed by other GA combinations. Effect of various treatments on quality has been limited.