Removal of early fruit branches modulated regulations in endotoxins delays senescence and improves boll opening, and yield in Bt cotton genotypes

Abstract Premature senescence, endotoxins attenuation and unopened bolls are chief deterrents to accomplish yield potential in cotton. An experiment was conducted with objectives to explore removal of early fruit branches (REFB) triggered regulations in biosynthesis of endotoxins (soluble proteins, proline, glycine betaine, phenolics) and their correlations with senescence and yield attributes of cotton. The experiment was conducted at two locations for period of two years using Randomized Complete Block Design under factorial arrangement and replicated five times. Treatments were comprised of combinations of REFB and two genotypes viz. T 1  = No REFB + FH-142; T 2  = No REFB + MNH-886; T 3  = REFB + FH-142 and T 4  = REFB + MNH-886. A considerable increase in soluble proteins, proline, glycine betaine, phenolics, first fruiting branch height, plant height at physiological cutout stage, total bolls per plant, sympodial branches and seed cotton yield per plant and significant decrease in unopened bolls per plant was observed by removing two early fruiting branches compared to no fruiting branch removal in both genotypes over the locations and years. While, more remarkable response for REFB was observed in MNH-886 compared to FH-142. Conclusively REFB modulated regulations in endotoxins delayed senescence, improved seed cotton yield since strong correlations of endotoxins with senescence and agronomic attributes were observed.