光温敏雄性不育水稻不育临界温度性状的遗传分析

光温敏不育系不育临界温度性状的稳定非常困难，其根本原因在于对这一性状的遗传模式缺乏了解。从粳型光敏不育系N5088S中分离出仅存在临界温度差异的H5088S株系，以两者为亲本，构建了包括正反交、回交及F2分离群体在内的7世代群体。将每粒谷苗一分为四而形成基因型构成相同的4套材料，每套材料进行不同温度处理，以花粉育性为指标采用IECM算法进行遗传分析。结果表明：四种温度条件下，正、反交F1育性差异不明显，表现低临界温度特性；F2在不同温度下育性分离比例不同，23.5℃处理下低临界温度对高临界温度为显性；不育临界温度符合两对主效基因和微效基因共同作用的混合遗传模型，主效基因的遗传力为80％-97％。

Genetic Analysis of the Low Critical Sterility Temperature Point in Photoperiod-thermo Sensitive Genic Male Sterile Rice

It has been a long haul but photoperiod- and thermo-sensitive genic male sterile (PTGMS) rice has not been freely used in hybrid rice production because there are two perplexing problems corresponding to the critical sterility temperature point (CSTP):the uncertainty of the CSTP segregating pattern and the instability of CSTP for every originally useful line.N5088S,the most widely commercialized japonica-type PTGMS line in China,also saw that its CSTP variants have been isolated but with all other agronomic characteristics unchanged.In this report we analyzed the genetic basis of CSTP,by employing the iterated expectation and conditional maximization (IECM) algorithm on four tiller-splitting-formed sets of seven generations from N5088S and its CSTP-variant H5088S,each set treated with one temperature regime.The main results indicated that there are two dominant major genes and polygene,as well as their respective epistasis conditioning the CSTP in the 23.5℃ regime.Based on the results obtained,the strategy for breeding of PTGMS lines with stable low CSTP was outlined.