Seed traits correlate with herbicide resistance in Italian ryegrass (Lolium perenne ssp. multiflorum)

BACKGROUND Italian ryegrass (Lolium perenne ssp. multiflorum) is one of the major winter annual weeds worldwide. In this research, diversity for seed morpho‐physiological traits such as seed weight, seed size, awnedness, dormancy, speed of germination, and seed vigor among Italian ryegrass populations collected from the Texas Blacklands region were assessed, and potential association with herbicide resistance was investigated. RESULTS A high degree of diversity was observed among the populations for 100‐seed weight (125–256 mg), seed length (4.8–6.6 mm), awn length (0–6 mm), and total seedling length (9–14 cm at 21 days after seed germination). Inter‐population range for seed dormancy was higher in the freshly harvested seed (31–85%), which reduced to 18 to 62% at 9 months after harvest. Populations with high initial seed dormancy (> 70% dormancy) released dormancy at a faster rate than the low dormancy group (