Manejo de regulador de crescimento no algodoeiro e seu efeito na produtividade e qualidade de fibra

Abstract

Growth regulators play a key role in managing cotton plant height by promoting a balance between vegetative and reproductive development. This control is essential to optimize production efficiency and ensure harvest quality. This study aimed to evaluate the effect of different rates of mepiquat chloride on the growth, yield, and fiber quality of cotton in the Sorriso region, Mato Grosso (MT), during the 2023 and 2024 growing seasons, using the cultivar FM 978GLTP RM. The experiment was conducted in a randomized block design with four replications, with the following treatments: Farm standard, Regula, Regula+25%, Regula+50%, Regula+100%, Regula+200%, and a control without regulator (only in the 2024 season). In the 2023 season, characterized by low water availability, there was no effect of the regulator management strategies on yield components, yield, or fiber quality, although the highest rate used (Regula+200%) resulted in shorter plants compared to the farm standard and Regula treatments. In the 2024 season, characterized by higher water availability and elevated temperatures, the absence of growth regulator led to taller plants, more nodes, lower average boll weight, and reduced yield. There was no significant variation between the regulator treatments for any variable, except for plant height, which was lower with the application of triple the recommended dose (Regula+200%) compared to the other regulator treatments, except for Regula+100%, which showed similar results. The findings indicated that the dose recommended by the Regula – Cotton Apps should be doubled to optimize height growth control in years with greater vegetative growth stimulus. It is concluded that increasing the dose of growth regulator reduces plant height but has no effect on yield or fiber quality.