小麦骨干亲本“周8425B”及其衍生品种的遗传解析和抗条锈病基因定位

 【目的】利用高密度分子标记解析了周8425B衍生品种的遗传结构，并鉴定其携带的抗条锈病基因。【方法】利用921个DArT（Diversity Arrays Technology）标记和83个SSR标记分析周8425B及其50份衍生品种（系）间的遗传结构和遗传区段传递，并利用关联分析定位抗条锈病基因。【结果】周8425B及其衍生品种的遗传相似性平均为67.6%，聚类分析结果与品种系谱来源基本一致。周8425B对其衍生一代、二代和三代的平均遗传贡献率分别为67.7%、63.6%和58.8%，在A、B和D基因组间遗传贡献率分别为 68.7%、62.0%和 59.4%。周8425B 对其衍生品种的21条染色体贡献率变幅为44.9%—70.9%，其中，对4A染色体贡献率最低，为44.8%，对1D染色体贡献率最高，达79.0%。利用DArT和SSR标记与成株期抗条锈鉴定结果进行关联分析，发现4个条锈病抗性位点（P＜0.01），其中2个条锈病抗性位点QYr.caas-2BL和QYr.caas-7BL与已报道的抗条锈病基因Yr7和YrZH84在相同染色体区段，另一个抗性位点QYr.caas-1BL与抗叶锈基因LrZH84位置相同，推测该位点与LrZH84紧密连锁或者一因多效。在3A染色体长臂末端发现一个条锈病抗性位点QYr.caas-3AL，与标记wPt-0398关联，可能是一个新基因，能解释22.9%的表型变异。【结论】骨干亲本对衍生后代在基因组和染色体水平上的贡献率主要与重要基因遗传传递有关，衍生品种携带的4个抗条锈病基因均来自骨干亲本周8425B，这些抗性基因及其它优异基因将在黄淮冬麦区南片品种遗传改良中继续发挥重要作用。

Genetic Diversity and Genome-Wide Association Analysis of Stripe Rust Resistance Among the Core Wheat Parent Zhou 8425B and Its Derivatives

【Objective】 Zhou 8425B is the most important core parent and has been widely used in the South Part of the Yellow and Huai Valleys Winter Wheat Zone. Understanding the principal components and detecting the wheat stripe rust resistance loci in Zhou 8425B will provide important information for the future genetic improvement of wheat varieties. 【Method】 The core parent Zhou 8425B and its 50 derivative varieties and lines were used to compare their genetic structure and components among different generations. Whole-genome association mapping was employed to identify the stripe rust resistance loci using 921 Diversity Array Technology (DArT) and 83 SSR markers. 【Result】The averaged genetic similarity index was 67.6% among Zhou 8425B and its derivatives, and the clustering results for these genotypes were basically in consistent with that from the pedigree analysis. On the whole-genome levels, Zhou 8425B had the contribution ratios of 67.7%, 63.6% and 58.8% to its first, second and third generation derivatives, respectively. The genetic contribution ratios of A, B and D subgenome levels were 68.7%, 62.0% and 59.4%, respectively. As for single chromosome level, 44.9% (4A) to 70.9% (1D) of Zhou 8425B alleles could be detected on the derivative varieties. Four loci were detected to be associated with stripe rust resistance by association mapping (P＜0.01), in which two loci QYr.caas-2BL and QYr.caas-7BL were found in the same genomic regions of Yr7 and YrZH84, respectively. A QTL QYr.caas-1BL was found in the same genomic region as leaf rust resistance gene LrZH84 reported previously, which might be attributed to be pleiotropic effect or tight linkage each other. A new locus QYr.caas-3AL was located on the long arm of chromosome 3A and linked with the terminal marker wPt-0398, explaining 22.9% of the phenotypic variance.【Conclusion】The contribution ratios transferred from the core parent to its derivatives on genome and chromosome levels were probably caused by various important alleles associated with agronomic traits and resistance genes. Four QTLs for stripe rust resistance detected in 50 derivative varieties were derived from the core parent Zhou 8425B. Therefore, it is presumed that these loci for stripe rust resistance and other important traits derived from Zhou 8425B could play important roles in the future wheat breeding program in China, especially in the South Part of the Yellow and Huai Valleys Winter Wheat Zone.