Impactos do regulador de crescimento TIBA em genótipos de soja

Abstract

Soybean is currently the main product of Brazilian agribusiness, cultivated across most agricultural regions of the country and under diverse production environments. In this context, the use of new technologies and inputs throughout the crop cycle has become increasingly important, including the use of plant growth regulators. It is known that in soybean, the growth balance between reproductive and vegetative structures and the occurrence of lodging are strongly correlated with the crop’s yield potential. However, despite advances in the use of some inputs and management strategies, the application of products aimed at modulating plant growth still lacks scientific validation. Therefore, this study aimed to evaluate the response of early and semi-early soybean genotypes to the growth regulator 2,3,5-triiodobenzoic acid (TIBA). The experiments were carried out at the UFLA’s Center for Development and Technology Transfer over two growing seasons, using a randomized complete block design in a strip-plot scheme. Treatments consisted of the combination of TIBA application across different soybean genotypes. A total of 15 early-cycle and 18 semi-early-cycle genotypes were used. TIBA was applied at the V5 phenological stage. The following traits were evaluated: grain yield, lodging, plant height, first pod insertion height, branching, number of grains, number of pods, and indices NDVIp, SPAD, NDVI, and NDRE (measured via UAV). Statistical analyses were conducted in R using the metan and lme4 packages, employing the F-test at a 5% significance level, followed by adjusted means grouping using the Scott-Knott test (1974). A significant effect of TIBA was observed for early-cycle genotypes, with yield gains. There was also a significant reduction in lodging and plant height, as well as an increase in days to maturity for genotypes of both cycles. Thus, it is concluded that TIBA has potential as a management tool to regulate soybean growth and development, potentially leading to yield improvements.