Effect of plant growth regulator application on agronomic traits and soybean yield - DOI: 10.4025/actasciagron.v30i5.5971

Abstract

The purpose of the work was to verify the effect of the application of a plant growth regulator on the agronomic traits of plants and on soybean seed yield, cultivar CD 216. The work was developed during two agricultural years (2005/06 and 2006/07). The treatments were composed by the combination of seed treatments (0 and 500 mL 100 kg^-1 of seeds) with three doses of plant growth regulator (250, 375 and 500 mL ha^-1) applied to the leaves in two stages of the culture’s development (V₅ and R₃), plus the control without application. The features evaluated were: plant height, number of seedpods per plant, yield and mass of one thousand seeds. The features of plant height and number of seedpods per plant were not influenced by the application of the plant growth regulator in the two agricultural years. In the agricultural years of 2005/06, the greater seed yield (2.927 kg ha^-1) was reached with the application of 211 mL ha^-1 of plant growth regulator to the leaves at the R₃ stage, together with seed treatment. In the second agricultural year there was no significant difference (p > 0.05) between the treatments in seed yield, although the results were superior to those obtained in the first year. One of the basic principles to improve the efficacy of the plant growth regulator in soybean crops is an adverse climatic condition.