Seed Germination Characteristics of Lolium multiflorum Populations from Wheat Fields of Eastern China

Lolium multiflorum is of worldwide agricultural importance as both a pasture crop and as a weed. We collected the seeds of 67 L. multiflorum populations from wheat lands in eastern China and three populations as commercial crop seeds; tested seed germination responses to temperature, osmotic potentials, and light/dark conditions; and also tested seed dormancy. Under constant temperatures, the germination percentages at 3 d after treatement (DAT) at 10, 15, 20, 25, 30, and 35 °C were 0%, 2.6 ± 0.5%, 37.1 ± 2.4%, 66.6 ± 1.9%, 68.2 ± 2.3%, and 37.3 ± 2.2%, respectively, and increased to 72.4 ± 2.0%, 95.6 ± 0.7%, 97.0 ± 0.7%, 98.3 ± 0.6%, 94.9 ± 1.0%, and 86.3 ± 1.2% at 14 DAT. The seed germination percentages in complete darkness at 14 DAT (averagely 87.4%) did not show significant differences with those in 12 h light/12 h dark treatment. The osmotic potential required for 50% germination (GO50) was −0.53 to −0.13 MPa, with an average of −0.38 MPa, and the average germination percentage under −0.6 MPa at 14 DAT was 0.9%. The germination percentages of freshly mature seeds stored for 0, 15, 30, and 60 d were 61.3%, 66.5%, 68.4%, and 88.0%. L. multiflorum populations collected from wheat fields with rice as the preceding crop (paddy fields) showed significantly higher germination percentages under 10 °C, and lower germination percentages under osmotic stresses, compared with those collected from wheat fields with corn as the preceding crop (drylands). This is the first report of L. multiflorum seed germination biology based on multiple populations with different sources in China and provides insights for improving its management strategies.