Morfofisiologia e produção de genótipos de algodoeiro colorido sob déficit hídrico em diferentes fases fenológicas.

Abstract

Water scarcity is one of the main limiting factors for the cultivation of several crops, especially in semi-arid regions. Cotton, despite being a water deficit tolerant crop, can have its physiological processes and productivity affected by this factor, so the use of deficit irrigation management strategies is an alternative to be considered. Thus, the objective of this work was to evaluate the growth, physiology, phytomass accumulation and production of naturally colored fiber cotton genotypes under water deficit in the different phenological stages of the crop. The plants were conducted in drainage lysimeters under field conditions, at the Federal University of Campina Grande, located in the municipality of Pombal, Paraíba. A randomized block design was used, in a 7 × 3 factorial scheme, corresponding to seven water deficit management strategies (1- A1B1C1; 2- A2B1C1; 3- A1B2C1; 4- A1B1C2; 5- A2B1C2; 6- A2B2C1; 7- A1B2C2) varying during the phenological phases of the crop (vegetative, flowering and fruiting) and three colored cotton genotypes (BRS Rubi, BRS Jade and BRS Safira). In the vegetative and formation phases of cotton production, water deficit irrigation can be used in cotton cultivation with the lowest losses in production components, which are negatively affected by water deficit in the flowering phase. Among the genotypes, BRS 'Jade' stands out for the highest mass of cotton seed, and BRS Rubi for the highest accumulation of dry phytomass of the aerial part, regardless of the development stage. Flowering and stress succession between phenological stages cause reductions in the production of naturally colored cotton at 120 days after sowing.