光温敏不育水稻不育性表达不稳定的遗传机制与原因综述

光温敏不育系不育性表达不稳定是近年来两系杂交水稻研究和应用中遇到的一大难题。为寻求克服这一难题的有效途径和方法，对不育性表达不稳定的遗传机制及其产生原因进行深入分析和探讨是十分必要的。界定了不育性表达不稳定的含义，综述了水稻光温敏不育系育性表达的种种复杂表现、不育起点温度漂变现象及其克服办法，着重论述了光温敏不育系不育性表达不稳定的遗传机制及原因。认为导致不育的起点温度受微效多基因控制是光温敏不育系不育性表达不稳定的遗传机制，不育起点温度上的遗传基础不纯或遗传杂合性是导致不育性表达不稳定的内在原因，并提出在育种上应充分考虑不育性表达的数量性状特征，采取花培育种途径或在杂交育种中采用系谱法和混合法相结合的后代选择方法，以达到选育不育性表达稳定的光温敏不育系的目的。

On Genetic Mechanism and Cause of Instability in Sterility Expression in Photoperiod- and Thermo-sensitive Genic Male Sterile Rice

The instability in sterility expression (ISE) of photoperiod and thermo sensitive genic male sterile (PTGMS) lines has been a difficult problem in the research and production of two line hybrid rice in recent years. To find out effective ways and methods to overcome this problem, it is necessary to deeply analyze and probe into the genetic mechanism and cause of ISE. The meaning of ISE was defined; the complexity of fertility expression of PTGMS lines, the drift of critical sterility inducing temperature (CSIT) of PTGMS lines and its overcoming method were summed up; and especially, the genetic mechanism and cause of ISE in PTGMS lines were intensively discussed. It is concluded that the genetic mechanism of ISE is that the inheritance of CSIT, which determines the sterility expression of PTGMS lines, is controlled by multiple micro genes, and the impurity of genetic bases or genetic heterozygosity in CSIT is the internal cause of ISE. It is suggested that the quantitative trait characteristic of sterility expression should be fully taken into consideration, so the breeding approach through anther culture should be adopted or the method combining pedigree selection with bulk selection in segregated filial generations should be used in cross breeding to increase the efficiency in breeding PTGMS lines with stable sterility expression.