Tolerância de genótipos de algodoeiro colorido ao estresse salino variando os estádios de desenvolvimento.

Abstract

The use of saline water in agriculture is becoming a reality in many areas of the world, being the variable salinity tolerance between stages of crop development, also varies with the genotype used. Equally important should be the recovery studies of plants, after the period of exposure to salinity, may be a strategy of using saline water for irrigation. In this sense the objective of this research was to determine the tolerance of naturally colored cotton genotypes, varying stages of plant development, in high and low salinity conditions and assess recovery after exposure to saline stress. In this sense, the objective of this research was to determine the tolerance of cotton genotypes during different stages of plant development under conditions of low and high salinity and assess recovery after exposure to saline stress. In an experiment conducted in a greenhouse of the Unidade Acadêmica de Engenharia Agrícola/CTRN, Campus Campina Grande, three cotton genotypes (G1 - BRS Rubi 1; G2 - BRS Topázio; G3 - BRS Safira) were evaluated submitted to seven managements strategies salinity varying the quality of applied at different stages of the plant cycle. The combined factors, in randomized blocks, resulted in 21 treatments (3 x 7) with three plants per plot and three replications. Variables were evaluated for growth, physiological and production plants at 16, 23, 30, 37, 44, 59, 93 and 113 days after sowing. Data were subjected to Fischer's test, comparing the averages Scott - Knott (p < 0.05) for the management strategies and Tukey test (p < 0.05) between cotton genotypes. Among the genotypes BRS Rubi was more sensitive to salinity of irrigation water (ECw 9 dS m-1), regardless of the stage of development. The successive application of saline water at flowering and formation of production was detrimental to growth and development and there was no recovery of plants after discontinuation of stress. Irrigation with saline water in the early stages of development can be used in the cultivation of cotton with the lowest losses in lint production. The production of cotton is more affected by salinity applied both at flowering and the formation of bolls.