Siberian Wildrye (Elymus sibiricus) Seed Vigor Estimation for the Prediction of Emergence Performance under Diverse Environmental Conditions

Seed vigor is an important aspect of seed quality. It is critical to predict seed vigor and plant seedling emergence under diverse environmental conditions using the laboratory vigor test. Accordingly, laboratory experiments were conducted to determine the standard germination (SG), early individual counts of radicle emergence (RE), mean germination time (MGT), and vigor index (VI) for 16 commercially available seed lots of Siberian wildrye (Elymus sibiricus), an economically and ecological important grass species. The field emergence (FE) for seed lots was explored using a three-year field trial from 2021 to 2023. Meanwhile, pot experiments were carried out to determine the seedling emergence performance under different environmental conditions, including control, drought, and salinity stress. The correlation and regression analysis were done to investigate the links between laboratory vigor test with emergence performance under both field and pot conditions. The results showed that the SG of 16 seed lots were high, similar, and did not differ significantly between seed lots. However, the seedling emergence performance (emergence percentage, seedling dry weight, and simplified vigor index) differed significantly between seed lots under both field and pot conditions. The SG was not significantly correlated with seedling emergence performance under either the field or pot conditions. The counts of RE at selected timing, MGT, and VI showed a significant relationship with seed vigor as reflected by seedling emergence performance under diverse environmental conditions, and we found that RE at 108 h was highly predictive of seed vigor and seedling emergence. The RE at 108 h and VI were positively related to seed vigor, while MGT was negatively related. The seed lots with low vigor had lower RE at 108 h and VI but longer MGT. Overall, both RE at 108 h, MGT, and VI can be used to estimate seed vigor and predict seedling emergence under different environmental conditions, and we highly recommend RE at 108 h as a quick, precise, and convenient vigor test and early warning sign for seed storage of E. sibiricus. These results will enable seed researchers, plant breeders, farmers, and government program directors to target higher seed vigor more effectively for E. sibiricus and similar grass species.