Growth and cotton yield over row spacing and growth regulator

Growth regulators and row spacing are an alternative to be considered and planned together and it consists in an effective technology in the establishment most profitable cotton crop. The main objective of this work was to evaluate the influence of row spacing in cotton crops and applications forms of growth regulator on components of cotton growth, production and yield for two growing seasons, 2007/08 and 2008/09 in Selvíria, state of Mato Grosso do Sul, Brazil. The experimental design was the completely randomized blocks arranged in bands and consisted in the following row spacing: 0.45, 0.70 and 0.90 m long. The management of growth regulator (mepiquat chloride - MC) was splitting in four applications (35, 45, 55, and 65 days after emergence - D.A.E.); single application at 70 D.A.E.; and there was no application. The use of growth regulator in a single application, as well in a split application, decreases plant height and stem diameter. Lower values for stem diameter, number of bolls and weight of 20 bolls were observed with the use of 0.45 m row spacing. Highest seed cotton yields were observed by splitting MC application and the use of sowing denser row spacing.