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水稻丽江新团黑谷(LTH)是一个云南地方粳稻普感品种,对全球近2 800多个稻瘟病菌生理小种均表现为感病表型。本研究为利用~(60)Co-γ射线辐照处理LTH种子,分单株收获M_1代种子。对M_2和M_3代植株分别进行稻瘟病的自然诱发筛选和人工喷雾接种筛选,以期从LTH中筛选获得抗性提高的突变体。在突变体筛选过程中,我们发现突变体的遗传背景受到零星异交或混杂干扰,这种情况在其他本底抗性水平较高的抗性突变体筛选中往往容易被忽略。为了确保突变体遗传背景的真实性,我们利用分布在水稻12条染色体上的在粳稻LTH与籼稻品种间存在多态性的In/Del标记,分析候选抗性植株是否为LTH纯合背景,以排除杂合假抗性个体。通过两种不同的筛选策略,最终从M_3代植株中分别鉴定出1份和4份抗性突变体,为进一步研究LTH普感特性奠定基础。将其中一个LTH抗病突变体分别与野生型LTH和籼稻普感品种CO39进行杂交,获得的F_2群体人工喷雾接种稻瘟病菌后调查抗、感植株的分离情况,分析结果显示,该突变体性状符合单个显性基因控制的遗传规律。另外,本研究结果表明:在水稻诱变育种工作中,不仅要做到充分隔离,还需借用分子标记辅助剔除零星意外串粉造成的杂合假突变体,以提高水稻突变体筛选的准确率。
Rice Lijiang Xintiaoheigu (LTH) is a endemic japonica rice variety in Yunnan. It has a susceptible phenotype to nearly 2 800 physiological races of Pyricularia grisea in the world. In this study, LTH seeds were irradiated with ~ (60) Co-γ rays and M_1 seeds were harvested separately. The M_2 and M_3 plants were screened by natural selection and artificial spray inoculation respectively, in order to select the mutants with improved resistance from LTH. During the mutant selection, we found that the genetic backgrounds of the mutants were sporadically crossed or intermixed, which is often overlooked in the screening of resistant mutants with higher background resistance. In order to ensure the authenticity of the genetic background of mutants, we used In / Del markers polymorphism between japonica LTH and indica varieties distributed on 12 chromosomes of rice to analyze whether candidate resistant plants are LTH homozygous background. Eliminate heterozygous false-resistant individuals. Through two different screening strategies, 1 and 4 resistant mutants were identified from M_3 generation plants respectively, which laid the foundation for further study on generalized features of LTH. One of the LTH resistant mutants was crossed with wild-type LTH and indica generalized CO39, respectively. The F2 population was inoculated with M. grisea to investigate the isolation of resistant and susceptible plants. The results showed that the mutant trait Conforms to the genetic law of single dominant gene control. In addition, the results of this study showed that not only the isolation should be sufficient, but also the use of molecular markers to help eliminate heterozygous false mutants caused by sporadic accidental stringing to improve the screening accuracy of rice mutants .