Response of plant growth regulators on flowering and fruiting in Alphonso mango trees.
Bhatt R. I., Sushil Kumar
Author Affiliation: Agriculture Experimental Station, Gujarat Agricultural University, Paria, District Valsad, Gujarat-396 145, India.
Gujarat Agricultural University Research Journal 22 : 88-95
Abstract : Field studies to evaluate the relative effectiveness of various plant growth regulators and other chemicals, namely KNO3 (2%), urea (2%), gibberellic acid (100 ppm) and paclobutrazol (Cultar at 2.5, 4 and 7.5 g a.i./tree as a soil drench), were carried out at the Agricultural Experimental Station, Gujarat Agricultural University, Paria, Gujarat, India, during 1990-93. Of the 4 growth regulators tested, paclobutrazol at 4 g a.i./tree in 5 litres of water, applied as soil drench to 25-year-old mango trees during the rainy season (end of August), recorded the highest flowering (85.82%), fruit set (322.66 fruits/tree) and yield (80.88 kg/tree) values, and lowest percentage fruit drop (17.08%). There were significant interactions between growth regulators and various stages of shoot growth, with respect to flowering and yield. The highest flowering (69.16%), fruit set (21.23 fruits set/20 shoots at marble stage) and yield (3.88 kg/20 shoots) values, and lowest percentage fruit drop (28.87%) were recorded on current year, mature shoots. Paclobutrazol (4 g a.i./tree) resulted in the best returns over the control (Rs?500.88/tree), thereby giving a cost-benefit ratio (CBR) of 1:12.52. However, paclobutrazol (2.5 g. a.i./tree) gave a higher CBR of 1:15.16. Cultar application tended to reduce vegetative growth and advanced flowering by 8-9 days compared with the control.