NITROGEN TOPDRESSING AT DIFFERENT PHENOLOGICAL STAGES AND COTTON CULTIVARS IN TANGARA DA SERRA-MT

Abstract

ABSTRACT: The study aimed at evaluating the vegetative development and productivity of cotton cultivars of in function of nitrogen application in different phenological, the experiment was carried out at Unemat, in the region of Tangará da Serra - MT, from January to July 2012. The experimental design used was the randomized blocks in factorial 3x5, with 3 repetitions. The treatments were constituted than five periods of application of the N topdressed accordance with developmental stage of cotton at the dose of 145 kg ha-1 of N for all treatments and three cotton cultivars. The evaluations of plant height, number of nodes per plant, number of apples per plant and shoot dry matter occurred at 120 days after emergence. Measurements of seed cotton yield were performed at 180. The experimental data were submitted to the Shapiro-Wilk normality tests and Levene homogeneity of variance, both at 1% significance level. Subsequently, we performed theanalysis of variance and applied the Duncan test to 5% significance. All the cultivars were shown to be indifferent in regard to the N application times in coverage. In productivity, the cultivar FMX 993 presented the largest production average.KEYWORDS: Gossypium hirsutum L., phenology, hybrids, of cotton productivity.