中文摘要：

在昆明孕穗期平均温度18．1℃的自然低温下，以云南当家品种滇屯502和合系35作轮回亲本，以548份云南稻核心种质为供体亲本配制的杂种BC1F2（458份）为材料，按籼粳、稻作区进行云南稻核心种质杂种后代形态性状遗传变异研究。结果表明：（1）杂种BC1F2具有丰富的形态多样性，结实率、实粒数、秕粒数、穗颈长等形态性状都表现出较大的变异，平均多样性指数也较高。（2）籼粳间、稻作区间单一性状变异趋势基本一致，但多样性指数存在一定差异。

英文摘要：

458 accessions hybrid BC1F2 were backcrossed, with two elite parents Diantun502 （Indica） and Hexi35 （Japonica） widely cultivated in Yunnan as recurrent parent, while 548 accessions core collection in Yunnan rice landrace as donors. Under natural low temperature 18.1 ℃ at booting stage, the genetic variation to main morphological characters of core collection hybrids in Yunnan rice landrace was analyzed between indica and japonica, rice cropping regions. The result showed that： （ 1 ）The hybrid BC1F2 had high morphological diversity among accessions, such as seed setting rate, filled grain no. per panicle, unfilled grain no. per panicle, peduncle length have and the average diversity index was high. （2）The variation trend of single characters was consistent between indica and japonica, rice cropping regions; There was great difference on diversity index among characters.