为了探讨水稻光温敏核不育系临界温度遗传稳定性问题，以连续6个世代的温敏核不育水稻96-5-2S（从培矮64S中选育出的新株系）为材料，研究了它们育性对低温的反应差异。结果表明,(1)在它们育性转换敏感期用23.5℃恒温冷水处理10 d(水深20 cm左右)或遇到2～3 d平均日均温22.9～23.1℃(平均日最低温21.7～22.0℃)的自然低温时，所有世代的96-5-2S均表现不育, 自交结实率为0, 花粉可染率为0～0.9%，世代间差异不显著;(2)在它们育性转换敏感期用21℃、22℃恒温冷水处理10 d或遇到4 d平均日均温22.9℃(平均日最低温20.7℃)的自然低温时，所有世代的96-5-2S均表现可育, 自交结实率为0.2%～7.1%,花粉可染率为1.1%～19.5%，世代间存在差异,随繁殖世代增加,花粉可染率与自交结实率有逐渐上升的趋势,当繁殖到第5代时，花粉可染率显著提高，当繁殖到第6代时，自交结实率显著提高。(3)对照培矮64S（05株系）在相同低温条件下，花粉可染率与自交结实率均极显著高于各世代的96-5-2S。以上结果说明, 随繁殖世代增加,96-5-2S的临界温度会发生缓慢的遗传漂移，到第5、6代时，就会在花粉与结实水平上明显表现出来，但不同世代间临界温度的差异小于不同株系（96-5-2S与培矮64S-05株系）间临界温度的差异，据此认为，通过单株选择是降低光温敏核不育系临界温度的重要途径。
In order to explore the genetic stability of critical temperature inducing male sterility of TGMS(thermo-sensitive genic male sterile) line , the response differences of fertility of consecutive 6 generational TGMS lines of 96-5-2S (developed from Pei’ai64S) to low temperature were studied in rice. The results were as follows: (1) All generational 96-5-2S lines were sterile with zero of selfed seed set setting rate and 0–0.9% of stainable pollen grains when they were treated with artificial cold water of constant 23.5℃(water depth 20 cm about) for 10 days or met natural cold air of average daily mean temperature 22.9–23.1℃(average daily minimum temperature 21.7–22.0℃) for 2–3 days at their thermo-sensitive stages inducing male fertility alternation(Table 1 and 2). (2) All generational 96-5-2S lines were fertile with 0.2%–7.1% of selfed seed setting rate and 1.1%–19.5% of stainable pollen grains when they were treated with artificial cold water of constant 21℃ and 22℃ for 10 days or natural cold air of average daily mean temperature 22.9℃(average daily minimum temperature 20.7℃) for 4 days at the same thermo-sensitive stages, but the selfed seed setting rate and stainable pollen grains percentage are different among different generations. As the multiplication generation increased, the bagged seed set and stainable pollen grains got more, and those of the 5th or 6th generation were significantly high than those of the first generation. (3) The selfed seed setting rate and stainable pollen grains percentage of Pei’ai64S (control) were much significantly higher than those of all generational 96-5-2S lines under the same low temperature condition. Based on above results, it is confident that the critical temperature of TGMS lines of 96-5-2S is genetically changeable slowly with the multiplication generation increase ,and this change will be obviously shown on the percentages of stainable pollen grains and selfed seed setting when 96-5-2S multiplicate to 5th or 6th generation respectively. However, the difference of critical temperature of 96-5-2S among different generations caused by genetically drift is less than that between 96-5-2S and Pei’ai64S. Therefore, it is a very important effective way to decrease critical temperature through pureline selection from the TGMS line population, which has relatively higher critical temperature.
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