Impact of Plant Growth Regulators on Yield and Fiber Quality in Cotton (Gossypium hirsutum)

Cotton (Gossypium hirsutum), usually known as ‘white gold’ is a perennial crop with an indeterminate growth habit and is grown as an annual crop in the agricultural system. Due to changing climatic conditions cotton has to face many stresses which can affect seed cotton yield and fiber quality. The change in climatic conditions and management practices can alter the behavior of cotton plants which is mostly due to the variations in plant hormone levels. To make cotton crops steady and get its full yield potential, the exogenous application of plant growth regulator (PGR) has imparted significant positive effects. In this study, three PGRs (auxin, cytokinin, and gibberellin at the rate of 1ppm/litter) were used to test their effect on seedlings of two established cotton varieties (FH-492 and FH-317) and for yield and fiber quality contributing traits in field conditions. Both the varieties responded differently to each PGR treatment at the flowering stage. The results revealed that PGRs do not affect seedlings to improve vigor and growth. However, yield contributing traits showed a positive response to PGRs by showing an increase in boll retention percentage up to 61%, boll weight up to 31%, seed cotton yields up to 40%, and 21% increase in ginning out turn (GOT%) compared to control. Auxin and gibberellin also increased fiber length (>5%) and decreased mic (<10%) to produce longer and finer fiber in both varieties. However, cytokinin showed a positive effect only on GOT% of both the varieties (18% in FH-492 and 11% in FH-317). Overall, the study demonstrates that exogenous application of plant growth regulators can enhance cotton yield and fiber quality, providing a promising strategy to improve crop resilience under changing climatic conditions