具野稻细胞质的胞质型雄性不育系的体细胞克隆变异II.体细胞克隆温敏核不育突变

Somaclonal Variation of Cytoplasmic Male S terile Lines with Wild Rice CytoplasmII. Somaclonal Thermo-sensitive Genic Male Sterile Mutation

摘要:

在胞质型水稻雄性不育系IR66707A和IR69700A经离体培养而获得的136个体细胞克隆中,发现了温敏核不育突变5例。这类突变体在广州地区的自然气候下,早季至晚季前期表现为不育,晚季后期表现为可育。盛夏,在幼穗发育至花粉形成阶段对部分突变材料进行短日照处理,发现对短日照敏感的不育系农垦58S转换为可育,而供试的5例突变及另一对照培矮64S却与未经处理的材料一样仍表现为不育,表明它们的育性与日照长度的变化无关。在同一发育时期进行低温处理的结果显示,低温处理10 d及10 d以上者可发生育性转换,自交结实率在17.23%-42.19%之间,而未经处理的材料仍然表现不育,表明它们的育性转换与温度有关。以正常品种为父本与突变体杂交,F₁全部为可育;F₂可育与不育个体的分离比为3:1;以F₁为父本与之测交,TF₁代中可育与不育个体的分离比为1:1。遗传分析表明,这种温敏核不育突变为一对隐性核基因所控制。获得了由胞质型雄性不育变为胞核型雄性不育的突变体,这在体细胞克隆变异领域中是一种典型的突变。

Abstract:

Among 136 somaclones, five mutants of thermo-sensitive gen ic male sterile rice were obtained by somatic cell culture from two male sterile (MS) lines, IR66707A and IR69700A, which are of cytoplasmic type. The mutants w ere sterile during late spring until early autumn, and became fertile in late au tumn (the end of October) in Guangzhou. In midsummer, when the mutants of young panicle developmental stage to pollen formation stage were used for short-day tr eatment (daylength was adjusted to 8 h daily for 30 days)，all the mutants were still sterile whereas the Nongken 58S (contro1) was converted to be fertile．However,when the mutants were treated under low temperature(22±1℃)for 10 or more days,they became fertile，the seed setting percentage being 17.23％-42.1 9％， whereas those under normal condition (high temperature) were still sterile．These results showed that the fertility conversion in mutants was correlated with temperature rather than with day length． If the mutants were used as female parent to cross with normal variety,the plants in F1 were all fertile，while in F₂ were segregated into 3(fertile):1(sterile)，and in testcross F₁ were in the ratio of 1：1． Genetical analysis indicated that the mutants were controlled by a pair recessive genes．In this experiment，we obtained a thermo-sensitive genic MS mutant that derived from cytoplasmic MS.