回交导入系稻瘟病抗性鉴定评价与分子检测分析

Evaluation for Rice Blast Resistance and Molecular Detection of Backcross Introgression Lines

【目的】通过对回交导入系进行稻瘟病抗性鉴定评价和分子检测,可以为水稻抗病育种和基础研究提供优质亲本和理论证据。【方法】利用优良杂交稻恢复系测253和桂649为轮回亲本,分别与3个水稻品种进行杂交、回交,构建了6个回交导入系群体。然后,采取自然诱发和人工接种方式对导入系进行稻瘟病鉴定评价,并结合分子标记技术检测导入系群体等位基因的分布频率。【结果】鉴定评价出抗穗颈瘟导入系68个,其中兼抗苗叶瘟的导入系有21个。最终筛选出广谱、高抗稻瘟病的优良恢复系4个。另外,卡方检测发现,由于稻瘟病抗性的定向选择,导入系选择群体在染色体5个位点上的等位基因发生了偏分离。【结论】回交导入系可以成为高效挖掘水稻优异基因资源以及培育优良水稻新品种的理想平台。

[ Objective ] Evaluation for rice blast and molecular detection of backcross introgression lines would supply elite parents and provide a theoretical basis to rice breeding for disease resistance. [ Method] Restorer line C253 and G649 were used as the recurrent parent to cross with 3 rice varieties, respectively. In the end, 6 backcross ILs populations were obtained. Evaluation of ILs population for rice blast resist- ance was carried out using the identification of natural infection in open field and artificial inoculation, respectively. Frequencies of alleles at different sites were detected with molecular marker technique in ILs population. [ Result]47 ILs resistant only to neck blast and 21 lines re- sistant to both neck and leaf blast were identified. In addition, 4 elite restorer lines with good resistance to blast were identified. Chi-square tests showed that 5 positions on chromosomes represented genetic segregation distortion. [ conclusion] The phenotypic and genetic information of ILs would be useful for efficiently mining desirable genes and developing superior varieties in the future.