Effects of Levels of Growth Regulator and Application Periods in Maize Genotypes on the Agronomic Traits

Abstract

The objective of this study was to evaluate the agronomic characteristics of corn hybrids short cycle on levels of plant regulator Stimulate® in two periods. The planting was done in field, in the experimental farm of the Mato Grosso do Sul State University. The experimental design was completely randomized, in a factorial scheme (3 × 2 × 2), with four replicates. The treatments consisted of three levels (0, 250 and 500 mL ha-1) of the plant regulator, with two hybrids (30A37PW Morgan and P3646-HY) and two times of application (vegetative stage and reproductive stage). The following averages were evaluated: plant height, number of leaves, tassel weight, tang weight, tang length, leaf weight, number of spikes, stem weight, stem diameter, ear diameter and whole plant weight. The number of leaves, number of spikes and stalk diameter were higher to P3646-HY and the tassel weight was higher to Morgan 30A37PW. The application of growth regulator of the doses of 250 and 500 mL ha-1, divided in the vegetative and reproductive stages, caused a reduction in stem diameter and whole plant weight, and in the other parameters the application in single dose and in divided dose did not affect plant growth. The genotype P3646-HY obtained higher number of leaves, number of spikes and stem diameter than the genotype 30A37PW Morgan, but this presented higher tassel weight.