Estratégias de manejo da irrigação em fases fenológicas do algodoeiro colorido.

Abstract

Cotton farming in the Northeast region of Brazil faces problems of water scarcity caused by irregularities in the rainy season, causing significant losses in cotton yield. In this context, the objective of this study was to evaluate growth, photochemical efficiency and the production of naturally colored cotton genotypes under water deficit management strategies in the phenological phases of plants. The research was carried out in the field at the Federal University of Campina Grande, located in the municipality of Pombal, Paraíba. A randomized block design was used, in a 3 x 7 factorial scheme, corresponding to three colored cotton genotypes (BRS Rubi, BRS Topázio and BRS Safira) in seven water deficit management strategies (40% of ETR) varying the phenological phases. Irrigation with water deficit during the vegetative phase promoted greater growth in naturally colored cotton genotypes. Irrigation with 40% of ETR in the vegetative and flowering phases promoted the highest quantum efficiency of photosystem II in colored cotton. In the vegetative and formation phases of cotton production, irrigation with water deficit can be used in cotton cultivation with the lowest losses in production components, which are negatively affected by the water deficit in the flowering phase. Among the genotypes, BRS Topázio stands out for the greater number of bolls and cotton seed, regardless of the stage of development.