Abstract
The objective of this work was to evaluate the tolerance of soybean (Glycine max) cultivars to flooding stress at different growth stages. The experiment was arranged in a 2x2x5 factorial arrangement, with two sowing dates (October and November), two soybean cultivars (TECIRGA 6070RR and NA 5909 RG), and five growth stages (SE-EM, EM-VC, VC-V2, V2-V4, and V6-V8) in the 2018/2019 and 2019/2020 crop years. The experimental design was completely randomized with four replicates. For both evaluated soybean cultivars, the growth stage most sensitive to soil flooding was SE-EM. After seedling emergence, the highest reductions in leaf area and shoot dry matter were observed in the V2-V4 stage, regardless of cultivar, sowing date, and crop year. From the V4 stage onwards, soybean shows a higher tolerance to flooding conditions. However, after seedling emergence, the TECIRGA 6070RR cultivar has a higher tolerance to flooding stress than NA 5909 RG. Sowing in October tends to reduce the impact of flooding stress on the plants.
Index terms
Glycine max; phenology; rice-soybean rotation; soil flooding; sowing dates