Resilience of soybean cultivars to drought stress during flowering and early-seed setting stages

Authors: POUDEL, SADIKSHYA - Mississippi State University; VENNAM, RANADHEER - Mississippi State University; SHRESTHA, AMRIT - Mississippi State University; REDDY, RAJA - Mississippi State University; WIJEWARDANE, NUWAN - Mississippi State University; Reddy, Krishna; BHEEMANAHALLI, RAJU - Mississippi State University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2023
Publication Date: 1/23/2023
Citation: Poudel, S., Vennam, R.R., Shrestha, A., Reddy, R.K., Wijewardane, N.K., Reddy, K.N., Bheemanahalli, R. 2023. Resilience of soybean cultivars to drought stress during flowering and early-seed setting stages. Scientific Reports. 13:1277. https://doi.org/10.1038/s41598-023-28354-0.
DOI: https://doi.org/10.1038/s41598-023-28354-0

Interpretive Summary: Drought stress during the soybean growing season and declining yield potential is a concern for soybean producers. In the Midsouthern US, the flowering and early pod setting stages face low and erratic rainfall, resulting in yield and quality. Scientists from Mississippi State University, Mississippi State, Mississippi and USDA-ARS, Crop Production Systems Research Unit, Stoneville, Mississippi have characterized ten soybean cultivars to identify drought-tolerant cultivars by exposing them to drought during the reproductive stage for 30 days. Pollen germination across cultivars was reduced by 17% under drought stress compared to the control. There was a significant positive relationship between pollen germination and seed weight under drought stress. A substantial reduction of stomatal conductance under drought stress increased the canopy temperature by 2°C. Drought stress decreased pod number (48%) and pod weight (42%), seed number (46%), and seed weight (35%). Interestingly, drought stress followed by rehydration increased the hundred or individual seed weight of southern US soybean at the compensation of seed number. In our study, variability in leaf reflectance properties and their relationship with physiological traits or yield suggested that leaf-level remote sensing information can be used for differentiating drought-sensitive soybean cultivars from tolerant ones. The stress tolerance of DM45X61 and LS5009XS confer the combination of physiological and yield traits under drought stress. The soybean cultivars with high phenotypic expression could provide a valuable resource for breeding under unfavorable climatic conditions.

Technical Abstract: Drought stress during the soybean growing season and declining yield potential raise concerns about yield loss and economic return. Given the challenges presented by drought stress, we characterized ten soybean cultivars to identify drought-tolerant cultivars by exposing them to drought during the reproductive stage for 30 days. Pollen germination across cultivars was reduced by 17% under drought stress compared to the control. There was a significant positive relationship between pollen germination and seed weight (r= 0.65, p < 0.05) under drought stress. A substantial reduction of stomatal conductance under drought stress increased the canopy temperature by 2°C. Drought stress decreased pod number (48%) and pod weight (42%), seed number (46%), and seed weight (35%). Interestingly, drought stress followed by rehydration increased the hundred or individual seed weight of southern US soybean at the compensation of seed number. Under drought stress, there were significant negative relationships between hundred seed weight and oil (r= - 0.73, p < 0.01), oil and protein (r= -0.79, p < 0.01). In our study, variability in leaf reflectance properties and their relationship with physiological traits or yield suggested that leaf-level remote sensing information can be used for differentiating drought-sensitive soybean cultivars from tolerant ones. The stress tolerance of DM45X61 and LS5009XS confer the combination of physiological and yield traits under drought stress. The soybean cultivars with high phenotypic expression could provide a valuable resource for breeding under unfavorable climatic conditions.