Harvest-aid herbicides influence soybean seed yield, quality and oxidative metabolism

Abstract

Harvest-aid herbicides are used to anticipate soybean harvest and make the field available for next crop during the growing season. However, this anticipation can interrupt the transport of photoassimilates and reduce seed yield, as well as affect the seed quality. It is also not well known if cultivars with earlier growth cycle are more sensitive to harvest-aid herbicides. This work evaluated how different moments of harvest-aid herbicides application affect soybean yield, seed physiological quality, and oxidative metabolism. Two cultivars were used, one early and another medium growth cycle. The herbicide used was paraquat. Experiments were carried out in the field to evaluate yield attributes, and from the seeds harvested, seed quality attributes were evaluated in controlled environment. Early application of harvest-aid herbicides reduced seed yield and 1000-seed mass in both evaluated cultivars, being more expressive for early growth cycle cultivar. Seeds from plants submitted to early application of harvestaid herbicides had higher enzymatic activity related to oxidative metabolism. The early growth cycle cultivar (maturity group - MG 6.2) produced more than the medium growth cycle cultivar (MG 7.7), however, had greater sensitivity to the early application of harvest-aid herbicide.