Influence of Soil Applied Boron on Growth, Boll Retention and Yield of Three Cotton Genotypes.

Cotton is the most important fiber crop of Pakistan due to its high valued fiber and contribution in domestic oil production. Cotton growers have serious concerns over premature shedding of flowers, squares and bolls. Micronutrients play distinctive role in plant physiological and biochemical processes and especiallyboron (B) deficiency in cotton hinders plant growth. A two years field study was conducted to quantify the effects of B application rates (@ 0.5, 1.0, 1.5, 2.0 and 2.5 kg ha^-1) on the growth, boll retention and yield of three cotton genotypes (FH-113, MNH-786 and CIM-496). Boron application significantly improved the growth, boll retention and yield of cotton genotypes. Results showed that the leaf area index (4.82), leaf area duration (292 days) and crop growth rate (5.85 g m^-2 day^-1) were significant in genotype FH-113 with soil B application (2 kg ha^-1). Similar trend was observed in yield related attributes in FH-113 with soil application of B at the rate of 2.0 kg ha^-1 which produced more bolls (25 bolls plant^-1), boll retention (37.31 %) and high seed cotton yield (2526 kg ha^-1). Results revealed that cotton genotype FH-113 performed best as compared to MNH-786 and CIM-496 genotypes with 2 kg ha^-1 of soil applied B.