Drought stress has transgenerational effects on soybean seed germination and seedling vigor

Authors: WIJEWARDANA, CHATHURIKA - Mississippi State University; REDDY, RAJA - Mississippi State University; KRUTZ, JASON - Mississippi State University; GAO, WEI - Colorado State University; Bellaloui, Nacer

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2019
Publication Date: 9/9/2019
Citation: Wijewardana, C., Reddy, R.K., Krutz, J.L., Gao, W., Bellaloui, N. 2019. Drought stress has transgenerational effects on soybean seed germination and seedling vigor. PLOS ONE. 14:1-20. https://doi.org/10.1371/journal.pone.0214977.
DOI: https://doi.org/10.1371/journal.pone.0214977

Interpretive Summary: It is well known that variations in environmental conditions such as photoperiod, water, nutrient status, and solar radiation can have a significant effect on soybean, resulting in yield loss and poor seed quality. Previous studies have reported that some effects of environmental stressors such as drought are transmittable and can have negative effects on the first set of offspring from parental generation (F1 generation). Therefore, the objective of this research was to determine if the effects of drought stress on parental soybean plants are transmitted to the F1 generation. The germination and seedling vigor of F1 soybean whose maternal parents, AG5332 and P5333RY, were exposed to soil moisture stress of 100, 80, 60, 40, and 20% of optimum moisture during reproductive growth, were evaluated under controlled conditions. Effects of soil moisture stress on the parents caused a reduction in seed germination rate, maximum seed germination, and overall seedling performance in the F1 generation. The effect of soil moisture stress on the parent environment induced seed quality that carried on the F1 generation seed gemination and seedling traits under optimum conditions and was further exasperated when exposed to increasing levels of drought stress. Results indicate that seed weight and storage reserve are key factors and positively associated with germination traits and seedling growth. Our data confirm that the effects of soil moisture stress on soybean are transferable, causing reduced germination, seedling vigor, and seed quality in the first (F1) generation. Therefore, optimal water supply during soybean seed formation period will benefit seed producers for optimizing seed quality and vigor characteristics of seed.

Technical Abstract: Temperatures that vary spatially and temporally over the soybean growing areas affect soybean seed yield and quality. Five day/night temperature, 21/13, 25/17, 29/21, 33/25, and 37/29'C, effects on total biomass, yield, and seed quality parameters were investigated on indeterminate (Asgrow AG5332, AG) and determinate (Progeny P5333RY, PR) soybean cultivars. The cultivar × temperature interaction was significant for total biomass, seed yield, protein, oil, palmitic acid, oleic acid, linolenic acid, raffinose, and stachyose. Quadratic functions best described the response of yield to temperature, where the optimum temperature for maximum yield was 26'C for AG, and 23'C for PR. Temperature affected all seed quality parameters in both cultivars. Seed protein concentration was slightly higher at the two lower and higher temperatures than at 29/21'C. Seed oil concentration increased with temperature up to 26'C for AG and 25'C for PR and declined at higher temperatures. Palmitic acids showed quadratic responses to temperature with a significant interaction between cultivars, while stearic acid showed a similar quadratic response in both cultivars. Oleic acid increased with increasing temperature while linolenic and linoleic acids declined linearly with temperature. Sucrose concentration declined with an increase in temperature in both the cultivars. Raffinose and stachyose concentrations in the two cultivars responded differently to temperature and declined with increasing temperature. The effects of temperature on yield and seed quality that are described in this research can be used to improve crop growth models and the management of soybean under climate change.