Selectivity of pre-emergent herbicides in soybean crops
Glycine max; phytotoxicity; productivity; antioxidant enzymes.
Soybean crops stand out as one of the main agricultural commodities in Brazil. However, the presence of weeds in agricultural areas can cause significant losses in the productivity of this crop. Chemical control is an effective and widely used management method for weed control through the application of herbicides. However, the excessive and indiscriminate use of herbicides has led to the emergence of resistant weed biotypes. Therefore, the use of pre-emergent herbicides in agricultural areas has been relevant as an effective and complementary tool for weed management, ensuring the good development of the crop after its emergence. In this context, the selectivity of pre-emergent herbicides is an essential factor for the adequate management of weeds in soybean crops, since the correct choice of herbicides ensures crop productivity. Therefore, this study aims to evaluate the tolerance of three different soybean cultivars to pre-emergent herbicides widely used in agricultural areas. To achieve this objective, two experiments will be carried out: one in the greenhouse with the objective of analyzing the physiological and metabolic effects of soybeans when subjected to pre-emergent herbicides through visual injury analysis, where scores will be assigned on a scale ranging from 0 to 100%, where 0% indicates the absence of symptoms and 100%, plant death, stomatal conductance, transient chlorophyll a fluorescence, analysis of the activity of antioxidant enzymes, Glutathione S-transferase enzyme and Glutamine Synthetase; and another will be conducted in the field with the objective of evaluating which of the three soybean cultivars is more tolerant to the herbicides studied through visual injury analysis and productivity assessment by counting the number of pods per plant, number of grains per pod and weight of 1000 grains. The data will be tested for normality using the Shapiro-Wilk test and the variances will be submitted to the F test and, in case of significance (p > 0.05), the Tukey test will be subsequently applied at a 5% significance level, using the R software. The results are expected to provide information on the selectivity of the pre-emergent herbicides tested in three soybean cultivars, evidencing differences in plant tolerance.