Abstract: Genetic variation of chaff and anther size and seed setting rate at indica rice cultivated region, and warm cool region of japonica rice, and mixed belt of indica and japonica rice cultivated using 15 crosses and five different cold tolerance parents.The results are as follows:(1) Narrow chaff, stable anther size and higher seed setting rate were observed in cold damage condition.There was a negative correlation between anther shorting rate and seed setting rate;and the weakest cold tolerance Towada was the most significant (0.924 ** ).(2)GCA is higher for Kunmingxiaobaigu and Lijing 2 with the strongest cold tolerance. Some near isogenic lines with cold tolerance have been bred using Kunmingxiaobaiogu and Lijing 2 for the donor of cold tolerance gene, and Towada for recurrent parents. (3) SCA and cold tolerance characters differ from generation and rice cropping regions.(4) Variation of indica character and cold tolerance gene accumulated at warm-cool region of japonica rice, and genetic evolution to indica characters.

Key words: chaff, anther, seed setting rate, genetic variation, rice cropping region, Yunnan rice, cold tolerance

摘要： 用5个不同耐冷级别品种按1/2p（p-1）配制15个组合及其亲本在籼稻区（F1）、籼粳交错区（F2）和温凉粳稻区（F1、F2、F3）进行云南稻种颖壳、花药大小和结实率的遗传变异研究，结果表明：（1）耐冷稻种在冷害条件下颖壳变窄、花药大小相对稳定、结实率较高，花药长缩短与结实率呈负相关或极显著负相关; 极弱耐冷品种十和田则呈极显著正相关(0.924**)。（2）极强耐冷的昆明小白谷、丽粳2号耐冷性状的GCA较高，用它们作耐冷基因供体、十和田作轮回亲本已获得一批耐冷性近等基因系。（3）不同世代同一稻区和同世代不同稻区的耐冷性状及SCA在不同稻区存在明显差异。（4）籼粳杂种后代在温凉粳稻区粳型性状变异同时伴随着耐冷基因的累积；而在籼粳交错区和籼稻区则有利于籼型性状的遗传进化。

关键词: 颖壳, 花药, 结实率, 遗传变异, 稻作区, 云南稻种, 耐冷性