Effect of arresting the late formed umbels by growth regulators spray on seed yield and seed quality in onion cv. CO (On) 5 (Allium cepa L.)

Abstract

The field experiment was carried out to study the effect of growth regulators spray on onion cv. CO (On) 5 seed production. The studies on the influence of foliar spray with growth regulators viz., benzylaminopurine at 60 and 90 ppm, mepiquat chloride at 500 and 750 ppm and brassinosteroid at 0.5 and 1 ppm spray were evaluated for restricting the late formed umbels. The growth regulators were sprayed at the time of flower stalk initiation (35 DAS) and 10 days after first spray. Among the growth regulators, brassinosteroid (1.0 ppm) was found to be effective in restricting the umbel orders at the optimum level of eight and reduced the duration for physiological maturity by 7 days when compared to control and enhanced the yield contributing characters viz., umbel diameter by 7.4%, number of capsules umbel -1 by 28.0%, number of filled capsules umbel -1 by 51.7%, seed set (%) by 11% and seed yield plant -1 by 4.7% over control and reduced the number of ill filled capsules umbel -1 by 7.2% and number of under sized seeds umbel -1 by 26.7% over control. It also improved the seed germination, drymatter production and vigour index by 3.4, 3.6 and 6.8% respectively over control. Hence, foliar spray with brassinosteroid at 1 ppm was found to be effective in restricting umbels orders and improving the seed yield and seed quality in onion.