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Exploitation of latent cool-injury resistance genes among rice cultivars grown in warm region.

温暖地区水稻品种潜在冷害抗性基因的开发利用

基本信息

批准号：
10660007
负责人：
OKUMOTO Yutaka
金额：
$ 2.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Exploitation of new genes for cold tolerance at booting stage of rice (Hereafter these genes are called tolerance genes for simplicity) was intended. To identify new tolerance genes, gene analyses for cold tolerance and development of new tester lines for cold tolerance were carried. Segregation analysis using F3 and F4 lines derived from the cross between EG3 (susceptible line) and EG5 (Aikoku : tolerant line) revealed that EG5 carried two complementary dominant genes for tolerance. Results from crosses of EG3/Aikoku3 (tolerant variety) and EG3/CTH5 (introduced tolerance from Hayakogane) suggested that both tolerant parents carried at least two tolerance genes. Comparing F3 lines derived from the cross combinations of EG3/Rikuu20 and EG3/Shinriki, most of the F3 plants were tolerant in the former combination while most of them were susceptible in the latter combination. This indicated that tolerance gene of Aikoku origin was dominant and that of Shinriki origin was recessive. Also, function of tolerance gene was investigated using CTH5 and near isogenic lines of Kirara397 for tolerence gene of Silewah (highly tolerant variety). Plants were put into the cold bath one month before the heading time (cold treatment) and effect of cold water on anther length, pollen fertility and seed fertility were observed. Irrespective of genotype for tolerance, all lines were severally reduced in anther length. Furthermore, anthers of plants grown under cold treatment become white and thin, while those of control plants were yellow and thick. For the relative anther length, lines with tolerance gene showed less reduction in it than the ones without tolerance gene. In pollen fertility, the former lines showed higher fertility than the later. Thus, it was suggested that effect of tolerance gene was expressed not only in pollen fertility but also in the growth of male reproductive organs.

本研究旨在发掘水稻孕穗期耐冷新基因（以下简称耐冷基因）。为了鉴定新的耐冷基因，进行了耐冷基因分析和耐冷新测验系的选育。对感病系EG 3和耐病系EG 5杂交的F3和F4进行分离分析，发现EG 5携带两对互补的显性耐病基因。EG 3/Aikoku 3（耐性品种）和EG 3/CTH 5（早子金导入耐性品种）杂交的结果表明，两个耐性亲本至少携带两个耐性基因。比较EG 3/Rikuu 20和EG 3/Shinriki两个杂交组合的F3代，前者F3代多数表现为耐病，后者F3代多数表现为感病。这表明，爱国起源的耐病基因为显性，新力起源的耐病基因为隐性。此外，还利用CTH 5和Kirara 397的近等基因系研究了Silewah（高耐性品种）耐性基因的功能。在抽穗前一个月将植株放入冷水浴中（冷处理），观察冷水对花药长度、花粉育性和种子育性的影响。不考虑耐药基因型，所有品系的花药长度都有不同程度的减少。此外，在冷处理下生长的植物的花药变得白色和薄，而对照植物的花药是黄色和厚。对于相对花药长度，带有耐抗性基因的株系比不带耐抗性基因的株系减少的幅度要小。在花粉育性方面，前者的育性高于后者。因此，表明耐性基因的作用不仅表现在花粉育性上，而且还表现在雄性生殖器官的发育上。