Physiological classification of drought tolerance in soybean genotypes

BUSTAMANTE, OM; POSADA, GA; SUAREZ P; ESPINOSA HERLEIN MA; MONTEOLIVA MI; GUZZO MC

Rosario

Congreso; Reunion Argentina de Fisiologia Vegetal; 2023

Drought is one of the most limiting environmental factors in agriculture. Water deficit reduces plant growth and alters development, reducing crop yields. Soybean is one of the most important crops worldwide in grain productivity and sown area. To improve productivity under drought, it is relevant to identify and characterize tolerant soybean genotypes. Drought tolerance could manifest in physiological responses, such as higher relative water content (RWC), fresh and dry biomass accumulation, or biochemical responses such as higher chlorophylls, proline, or FRAP, or lower MDA (oxidative damage). This project aimed to classify soybean genotypes under controlled drought. We evaluated soybean lines from EEA Marcos Juárez (INTA), grown in greenhouse, with supplemental light and temperature control. All plants were well watered until the second trifoliate leaf emerged. Then, half of the plants were subjected to water shortage. They were daily monitored until soil moisture reached 30% of soil maximum capacity and kept at that level for one more week, when they were measured and harvested. We found variability in stress responses, with genotypes that keep higher RWC than 70%. Greenness increased under drought for all materials. We also found variability in proline, FRAP and chlorophylls