Preliminary identification and evaluation of high quality rice germplasm resources for cold tolerance under natural low temperatures during 2009

[Objective]The germplasm with strong cold tolerance was screened out from the tested rice germplasm to provide materials for application in breeding of cold tolerant rice varieties.[Method]Under natural low temperature conditions of early spring and cold dew wind at late rice cropping,458 high quality rice germplasm resources were preliminary analyzed and evaluated for cold tolerance during sprouting,seedling,and flowering stages,using early sowing-early planting and late sowing-late planting methods.[Result]The germplasm number 21,15 and 76,5 and 80 showed very strong and strong cold tolerance at sprouting,seedling and flowering stage,which accounted for 4.59,3.28 and 16.59,1.48 and 23.74%,respectively.Cold tolerance of different germplasm at different growing stages was not entirely consistent,but the germplasm with strong cold tolerance at sprouting stage commonly showed stronger cold tolerance at seedling stage.Six specimens,viz.,TKM10,Sanlicun,Xiangwanxian 13,Hui 968xuan,649/Wudadaozhong//649///649 and 253/P117//253///253 were screened out,which showed strong or very strong cold tolerance at several growing stages under natural low temperature.[Conclusion]The high quality rice germplasm materials,with strong or weak cold tolerance,were distinguished under natural low temperature conditions.The germplasm with strong or very strong cold tolerance has fairly good application value.Six screened germplasm materials with strong or very strong cold tolerance at several growing stages under natural low temperature can be used as parent materials in research and breeding of cold tolerant rice varieties.