水稻纹枯病抗性关联分析及抗性等位变异发掘

采用苗期微室接种鉴定法，用144个分布于水稻全基因组的多态性标记，利用TASSEL软件GLM (Q)、MLM (Q+K)和MLM (PCA+K) 3种模型对456份水稻材料组成的自然群体进行纹枯病抗性关联分析。结果发现，有13个标记位点至少在两种模型中均被检测到与纹枯病抗性显著关联，单个位点可解释表型变异的1.84%~8.42%；其中10个标记位点位于以往报道的连锁定位的抗纹枯病QTL附近，3个标记位点(RM1036、RM5371和RM7585)是未曾报道的新的抗病相关位点。抗性等位变异RM7585-150对纹枯病发病病级减效效应最大；有259份材料携带抗性等位变异RM5371-129，占供试材料总数的56.8%，只有26份材料携带抗性等位变异RM1036-82，占供试材料总数的5.7%。水稻纹枯病发病病级与其含有的抗性等位变异数量呈极显著的负相关。本研究结果将为水稻抗纹枯病分子标记辅助育种提供理论依据。

Association Mapping and Resistant Alleles Analysis for Sheath Blight Resistance in Rice

To identify and map sheath blight (ShB) resistance loci in rice, we carried out association analysis of 456 rice accessions using 144 genome-wide markers based on GLM (Q), MLM (Q+K), and MLM (PCA+K) models of TASSEL software. The phenotyping were assayed at the seedling stage with a micro-chamber screening method. The results showed that thirteen markers were significantly associated with ShB resistance detected by using at least two models, which explained from 1.84% to 8.42% of the phenotypic variance. In addition, ten of the identified resistant loci were either quite near or within the interval of previously identified QTLs. RM1036, RM5371, and RM7585 were novel resistant loci that had not been previously reported. The resistant allele 150 of RM7585 showed the largest negative effect to ShB rating, allele 129 of RM5371 existed in 259 (56.8%) of 456 rice accessions, and 82 of RM1036 existed in 26 (5.7%) rice accessions. The number of putative resistant alleles presented in rice was highly and significantly correlated with the decrease of ShB rating. The resistant alleles identified in this study are readily available and can be exploited for marker-assisted selection.