Crescimento, fisiologia e produção do algodoeiro sob efeito do silício via foliar

Abstract

The cotton crop is considered a crop of significant socioeconomic and environmental importance. Its productive chain is on the second economic activity in the world, and the crop is considered trinit y for providing fiber, oil and energy. The productive chain of this oilseed crop still suffers by the lack of full utilization of appropriate technologies, which requires development and implementation of such technologies. The use of silicon in agriculture has shown promise in optimizing morphophysiological and biochemical aspects, as well on yield of plants. Another effective practice is the use of ecologically adapted cultivars to soil and climate conditions from ecosystems of cultivation. The aim of this work was to evaluate the growth, physiology and yield of cotton cultivars on leaf application of silicon. The experiment was carried out at Embrapa Algodão, Campina Grande, PB, Brazil, in a completely randomized design, mounted on 3 x 5 factorial scheme, with three cotton cultivars ( BRS Topázio , BRS Safira and BRS Rubi ), five concentrations of silicon (0 , 50, 100, 150 and 200 mg L -1 ), with four replications, applied weekly, by leaf application. Biometric, physiological, biochemical aspects and yield were evaluated. The data were submitted to analysis of variance, regression, correlation and mean test. Treatments had significant effect on growth, physiological, biochemical and yield variables. Evaluating the effects of factors it was found that the cultivars were different in relation to the analyzed aspects. It was recorded that concentrations of silicon promote significant variations on biometric, physiological and biochemical aspects. There were no differences on production and yield of cotton in response to silicon applications. On BRS Topázio cult ivar, the silicon increased the rate of stem expansion, photosynthesis, fluorescence of chlorophyll a , total chlorophyll and carotenoids. The application of silicon on BRS Safira increased plant height, growth rate, total chlorophyll, carotenoids and relative water content in the leaf. On BRS Rubi , the silicon increased the plant height, stem growth rate, fluorescence of chlorophyll a , photochemical efficiency and relative water content in the leaf. Silicon reduced the cellular extrusion in the three evaluated cultivars.