Abstract
A field trial was conducted to study the comparative- response of two varieties of cotton. i.e. 8-557 and I H-f2 to NAA and IAA foliar applications, alone as well as in combination, sprayed once. and twice 30 and 55 days after sowing. In both the varieties, a significant increase was obrIved by hormones in various pa.rarne-ters like height of plant, number of branches, number of seeds per boll, 100-seed weight and seed cotton yield. NAA proved more effective than IAA and their combination while double spray yielded better results than single spray, Both the varieties responded differently to the two hormones and differed significantly from each other for days taken to flowering and boll formation. Compara-tively B-557 exhibited less shedding than 11-1-62 after hormone application,
INTRODUCTION
Cotton yield can be increased to a great extent if shedding of flowers and bolls is prevented or minimized. Since the discovery of IAA, the use of growth hormones has become a common feature of modern agriculture. IAA can share its effectiveness with chemicals like NAA and can cause an increase in yield. The proper amount, time and method of application of these hormones have been found to be of great significance in various crops. The foliar spray of 0.5 IAA increased seed cotton yield as observed by Prokof rind Rasulov 0970, Chowdappan et 01. 0979) observed that 20 ppm and 30 ppm IAA increased the number of boils per plant in cotton cuItivar NICU-8, As regards the time of application, Khan and Hanif 0980) recorded that one to three sprays of 20 ppm NAA from I5th July to 30th August resulted in maximum seed cotton yield. Different varieties of a crop may respond differently to these. hormones due to differences in genetic make up. Mote et a! (1975) observed that when Capsimn arm L. was sprived with NAA, rower drop was controlled in alI
