A seed vigour test based on radicle emergence during germination at 5C for four forage species

Forage species play important role in both livestock production and environment protection. Seed vigour is a critical aspect of seed quality. The objective of this study was to develop a seed vigour test based on radicle emergence at a low temperature for four important forage species, Lolium multiflorum, Coronilla varia, Astragalus sinicus and Vicia sativa. The standard germination test (20 degrees C) (SG) and cold radicle emergence (CRE) to = 2 mm during germination at 5 degrees C were determined for seed lots of four species in the laboratory. Field emergence (FE) was also measured, in April 2022. For four species, the SG of seed lots were high and similar, and was not significantly related to FE. However, the CRE counts at 11, 14, 18 and 7 days from sowing for L. multiflorum, C. varia, A. sinicus and V. sativa, respectively, were well correlated with FE, with coefficients of determination (R2) of 0.757, 0.815, 0.774 and 0.812, respectively (P < 0.01). These findings suggested that CRE during germination at 5 degrees C has good potential in assessing FE and hence seed vigour for four forage species.