Transgenerational Inheritance of Soil Moisture Stress Induced Loss on Soybean Seed Germination.

Seed germination in many plant species is governed by the environment under which its parent plants were raised and matured. Prior studies have shown that stress-induced responses are inherited through plants’ trans-generational memory. Soil moisture stress that occurs during soybean seed fill greatly reduces seed yield, but less attention has been paid to determine its influence in expression of traits on offspring. In this study, we tested the hypothesis that soybean seeds formed after exposure to different soil moisture stress levels would affect the seed based traits in next generation. Initially, two soybean cultivars; Asgrow 5332 and Progeny 5333 were grown at five levels of evapotranspiration (ET) (100, 80, 60, 40, and 20% ET) of irrigation treatments under sunlit environmental conditions at flowering stage. Then, seeds obtained from these treatments were tested for seed germination vitality traits at five different in-vitro osmotic stress treatments using polyethylene glycol (PEG 8000) solutions which mimic water potentials ranging from 0.0 to −0.9 MPa with -0.2 MPa increments and incubated at 25 °C. Maximum seed germination, time to 50% germination, and seed germination rate were derived by using appropriate regression analysis. Cultivars differed significantly for the seed-based traits and significantly decreased with decreasing osmotic potential. Soil moisture stress induced irreversible change in seed quality of the offspring where the damage was increased further when exposed to same type of stresses. The results suggest that the stress-induced memory from previous generations can possibly be carried over, persuading flexibility to stress damage in the successive generations.