Gas exchange, growth, and production of cotton genotypes under water deficit in phenological stages

-Cotton cultivation in the Brazilian Northeast region faces water scarcity problems caused by the irregularity of the rainy season, leading to losses in yield. In this context, the objective of the present study was to evaluate the gas exchange, growth, and production of colored-fiber cotton genotypes under water stress, varying the water deficit management strategies in the different phenological stages of the plant. The study was carried out in the experimental area of the Federal University of Campina Grande, located in the municipality of Pombal, Paraiba, Brazil. A randomized block design was used, in a 3 x 7 factorial scheme, corresponding to three colored cotton genotypes ('BRS Rubi', 'BRS Jade', and 'BRS Safira') and application of water deficit (40% of actual evapotranspiration -ETr) management strategies in seven phenological stages of the crop. The 'BRS Jade' genotype is the most suitable for cultivation under water deficit conditions with 40% of the actual evapotranspiration. Colored-fiber cotton cultivation under water deficit in the flowering stage caused a reduction in physiological variables and growth. Water deficit during the vegetative and yield formation stages promoted lower losses in the production of seed cotton and total seed weight of the genotypes 'BRS Rubi', 'BRS Jade', and 'BRS Safira'.

Automated summary

Cotton cultivation in the Brazilian Northeast region is affected by water scarcity due to irregular rainy season, resulting in decreased yield. This study evaluated the impact of different water deficit management strategies on gas exchange, growth, and production of colored-fiber cotton genotypes at various phenological stages. The 'BRS Jade' genotype was found to be the most suitable for cultivation under 40% of actual evapotranspiration water deficit. Water deficit during flowering stage reduced physiological variables and growth, while deficit during vegetative and yield formation stages resulted in lower seed cotton production and total seed weight for genotypes 'BRS Rubi', 'BRS Jade', and 'BRS Safira'.