水稻光温敏核不育系起点温度遗传纯化的策略探讨

提出了光温敏核不育系育性遗传由两种不同类型基因控制的假说，对光温敏核不育系起点温度“漂变”的原因进行了解释。在遗传和统计分析的基础上，对高世代水稻光温敏核不育系起点温度遗传纯化的策略进行了探讨，提出了相应的选育技术路线和方法，以解决现有光温敏核不育系育性表达不稳定的问题。

A Discussion on Genetically Purifying P(T)GMS Rice Lines in Critical Sterility Inducing Temperature

It is found that the existing photo-thermo-sensitive genic male sterile (P(T)GMS) lines in rice show, to some extent, individual difference of critical sterility inducing temperature (CSIT) in fertility alteration among a population, and the shift of CSIT to a higher level occurs with the multiplied generations increased, which results in a rapid degeneration of P(T)GMS lines and soon causes them unusable in practice. Based on previous reseach findings, a hypothesis is put forward to explain the reason of CSIT changing in P(T)GMS lines. The hypothesis postulates: the inheritance of fertility in P(T)GMS lines is controlled by two kinds of genes, i.e., fertility alteration, belonging to a qualitative character, is controlled by one or two pairs of recessive nuclear genes, while the CSIT, belonging to a quantitative character, is controlled by polygenes. According to the hypothesis, the reason why the CSIT of a completely male sterile plant selected from a P(T)GMS line changes and segregates in its filial generations is that a few of heterozygous polygenes still exist in the genotype of the selected plant. By way of genetical and statistical analysis, a technical procedure has been designed to genetically purify the existing P(T)GMS lines in CSIT, i.e., to develop P(T)GMS lines with homozygous polygenes in phytotron. The procedure includes scrceening of single plants, identifying for the fertility of each family line from individual plants under different controlled temperatures.