不同年代籼稻品种生育早期耐冷性差异OA

Frequent low-temperature stress in early spring occurs in the rice-growing regions of southern China,seriously restricting the stable production of indica rice.Systematically exploring and utilizing elite cold-tolerant germplasm resources is therefore an urgent need for cold-tolerance breeding in indica rice.In this study,298 representative conventional indica cultivars developed across different breeding eras in China were used to systematically evaluate 16 key cold-tolerance traits at the germination,bud,and seedling stages in an artificial climate incubator.Comparative and cluster analyses of cold-tolerance traits across eras were conducted to elucidate the evolutionary pattern of cold tolerance in indica rice.The results showed that:Cold tolerance exhibited significant stage specificity,with weak correlations among the germination,bud,and seedling stages,indicating largely independent genetic bases;Cold tolerance has been progressively improved over breeding eras,and modern cultivars(A2000s)performed significantly better than early cultivars at all stages,with seedling survival rate increasing from 37.49％-43.27％in early cultivars to 56.39％;Phenotypic clustering classified the cultivars into three groups and revealed a clear enrichment trend from Group Ⅲ(intermediate type)and Group Ⅱ(sensitive type)toward Group Ⅰ(strong cold-tolerant type),within which modern cultivars accounted for 56.19％;Eighteen elite germplasm lines with strong cold tolerance at the germination,bud,and seedling stages,such as Huangyuesimiao and Nantezhan,were identified from Group Ⅰ and showed consistently superior performance across all stages.This study clarifies the stage specificity and breeding-era evolution of early cold tolerance in indica rice,and provides elite germplasm resources valuable for breeding practice,offering both theoretical support and material foundations for the genetic improvement of cold tolerance and the development of new cold-tolerant indica cultivars.