<b>Application systems of growth regulator with different plant densities in upland cotton cultivars (<em>Gossypium hirsutum</em> L. var. <em>latifolium</em> Hutch.)</b> - DOI: 10.4025/actasciagron.v26i1.1966

Abstract

The cotton crop management for plant population, cultivars and growth regulator application system to adequate the plant architecture are technical aspects of relevant importance. The present work was developed at the experimental station of the São Paulo State University/Ilha Solteira Campus, State of São Paulo, Brazil, in a Dark red latosol. The experimental design was the randomized completely blocks with twelve treatments and four replications, arranged in a factorial scheme 2x3x2, aiming to study: cotton cultivars (IAC 23 and CNPA ITA 90), plant density (6, 10 and 14 plants m^-1); application systems of growth regulator (mepiquat chloride) with single application at 72 days after emergence (DAE) (1,0L ha^-1) and in four times (0,1; 0,2; 0,3 and 0,4L ha^-1), at 28, 43, 57 e 72 DAE. It was concluded that the application systems of the growth regulator do not affect the yield. The cotton plants with parceled application of growth regulator showed lower values of stem diameter and height when compared with single application. The IAC 23 presents stem diameter higher than the CNPA ITA 90. The CNPA ITA 90 presents fiber percentage higher than the IAC 23. The effect of growth regulator application system under the plant height depends of the plant population and the cultivar. The CNPA ITA 90 presents higher averages of fiber length, uniformity and tenacity. The parceled system of growth regulator application presets the higher values of uniformity and fiber length