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

Abstract

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, Paraíba, Brazil. A randomized block design was used, in a 3 × 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’.

Irrigation Strategies with Controlled Water Deficit in Two Production Cycles of Cotton

“…Thus, it can be seen that ‘BRS Jade’ had greater production potential in both cycles. This is justified by the genetic constitution inherent to the genotype, allowing it to have superior agronomic characteristics when compared to the other genotypes studied [ 42 ], favoring the use of ‘BRS Jade’ as a genetic material suitable to sustainable agricultural exploitation [ 43 ].…”

Tolerance of sour passion fruit cultivars to salt stress in a semi-arid region

“…When comparing the assimilation rate of plants irrigated with water of 3.5 dS m -1 to that of plants that received water of 0.3 dS m -1 , a decrease of 56.33% was observed. The reduction in the photosynthesis rate of sour passion fruit plants under salt stress conditions is related to the action of stomatal and non-stomatal factors, such as the restriction of CO 2 diffusion in the mesophyll cells and a decrease in the affinity of ribulose-1,5-biphosphate carboxylase-oxygenase (RuBisCO) with CO 2 (Soares et al, 2023), including changes in chlorophyll and carotenoid concentrations (Dias et al, 2019;Diniz et al, 2020). Silva et al (2019), when evaluating the gas exchange of passion fruit as a function of irrigation with saline waters (ECw ranging from 0.7 to 2.8 dS m -1 ), observed that the lowest CO 2 assimilation rate (8.18 μmol CO 2 m -2 s -1 ) was obtained in plants irrigated with water of 2.8 dS m -1 .…”

Aplicação de quitosana no cultivo do algodoeiro de fibra colorida ‘BRS Jade’ sob restrição hídrica

“…Although cotton plants are relatively tolerant to water deficits, the expansion of cotton farming in the Brazilian semiarid region is constrained by local water conditions. Research on cotton crops under water restrictions has shown that water scarcity, particularly during critical phases like flowering and boll formation, directly impacts plant growth, development, and ultimately the productivity and quality of the fibers (Cordão et al, 2018;Maniçoba et al, 2021;Soares et al, 2023).…”