Distribution of the Rice Diversity Panel 1 accessions by subpopulation group for cold tolerance at germination.

<p>Cold tolerance described as the “Germination Index” was calculated as the ratio of the mean percentage of seeds with coleoptiles >5 mm under cold treatment to the mean percentage of seeds with coleoptiles >5mm under warm treatment. The <i>temperate japonica</i> and <i>tropical japonica</i> accessions were significantly more tolerant than accessions classified as <i>indica</i> and <i>aus</i>, the <i>INDICA</i> subspecies. Based on the Student’s t-test (p<0.05) there were no differences between <i>indica</i> and <i>aus</i> subpopulations.</p>