Use of growth regulators to manipulate alternate bearing rhythm in mango (Mangifera indica L.).
Ravishankar H., Nalawadi U. G., Hulamani N. C.
Author Affiliation: College of Agriculture, University of Agricultural Sciences, Dharwad 580?005, Karnataka, India.
Karnataka Journal of Agricultural Sciences 6 : 7-12
Abstract : Field trials were conducted with 30-year-old alternate-bearing trees of cv. Alphonso to compare the effectiveness of different growth regulators for inducing flowering in the off-year on shoots that had borne a crop in the previous season. TIBA at 100 or 150 p.p.m., Ethrel [ethephon] at 250 p.p.m. either alone or with 1% KNO3 or 1% urea, CCC [chlormequat] at 500 or 1000 p.p.m., Alar [daminozide] at 500 or 1000 p.p.m., and Atonik [nitroguaiacol + nitrophenolate] at 1:1000 either alone or with 1% urea, were compared. Seven foliar sprays, with a wetter, were applied at 15-day intervals to the trees from early Sep. to early Dec. in 1983 and 1985. Application of TIBA at 100 p.p.m. resulted in the maximum flower bud induction (77.3%), directly on fruited shoots, bypassing the vegetative growth expected in the off-year. TIBA at 150 p.p.m. gave 69% induction and CCC at 500 p.p.m. gave 67.7% induction on fruited shoots. Atonik (alone or with urea) was the only ineffective compound; its application resulted in maximum induction (73.3%) of new vegetative growth on fruited shoots. No such vegetative growth was produced using CCC at 500 p.p.m. and very little with Alar at 500 p.p.m. or TIBA at 100 or 150 p.p.m. The only compound which proved effective in inducing flowering on new vegetative shoots that developed subsequently on fruited shoots was CCC; induction was 25.7 and 21% with 500 and 1000 p.p.m., respectively. The maximum total induction (93.3%) of flowering on fruited shoots during the expected off-years was obtained in trees sprayed with CCC at 500 p.p.m., followed by TIBA at 100 p.p.m. (85%) and TIBA at 150 p.p.m. (73.7%).