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【目的】利用高密度SNP标记解析骨干亲本京411的遗传结构,并研究其根系性状遗传特征,为培育高产广适性品种奠定基础。【方法】选用京411及其14个衍生品种(系),包括衍生一代6份,衍生二代8份,每品种选取饱满且大小一致的种子在发苗网上生长6 d,每份材料选取大小一致的幼苗转移至培养盘,每个培养盘种植3次重复,连续培养15 d后测定苗期根部性状的最长根长、侧根长、主根长、总根长、侧根表面积、主根表面积、总根表面积、总根尖数和根系干重。利用90K SNP芯片分析京411及其衍生后代群体的遗传结构和遗传区段传递,结合逐步回归分析定位苗期根部性状基因,探讨京411携带的优异根系基因在衍生后代中的分布。【结果】京411衍生群体平均遗传相似性为57.9%,该亲本与其衍生一代和衍生二代相同的等位变异频率分别为63.9%和67.9%,显著高于理论值。在A、B和D基因组间的相同等位变异频率分别为62.2%、61.3%和74.3%。京411的侧根和根尖数均优于其衍生品种,衍生品种的主根长和根干物质重量等性状的改良较为显著。以已有定位信息的SNP标记与根系性状进行逐步回归分析,共发掘出35个根系性状位点,3DL和5BL上携带控制根长性状的主效位点,分别与SNP标记wsnp_Ex_c1032_1972861和BS00100708_51关联,可用于京411衍生群体中分子辅助选择。来自京411的26个位点对根部性状起正向效应,中麦175和CA0958携带正向效应区段最多,占正向效应位点总数的73.1%。【结论】传统育种对地上部农艺性状的选择,可有效促进地下根系的改良,相当于对优异性状遗传片段的聚合。在京411衍生群体中,中麦175是针对骨干亲本遗传改良最成功的品种,不仅携带较多的京411优异根系基因,而且其主要根系性状、产量表现及广适性均优于京411。
【Objective】 The genetic structure of Jing411, a key parent, was analyzed by using high-density SNP markers, and the genetic characteristics of root traits were studied, which laid the foundation for cultivating high-yielding and adapting varieties. 【Method】 Jing 411 and its 14 derivatives (lines) were selected, including 6 derived and 6 second derivative generations. The seeds of full size and same size were selected for growing for 6 days on each seedling. Each material was selected for size The same seedlings were transferred to the culture plate and each plate was planted three times. After continuous culture for 15 days, the longest root length, lateral root length, main root length, total root length, lateral root surface area, main root surface area, Root surface area, total root tip number and root dry weight. The 90K SNP chip was used to analyze the genetic structure and genetic transmission of Jing 411 and its derived progeny population. Combined with stepwise regression analysis, the root traits of seedlings were mapped to explore the distribution of excellent root genes carried by Jing 411 in the derived offspring. 【Result】 The average genetic similarity of Beijing 411 population was 57.9%. The same allelic frequencies of the Beijing 411 population were 63.9% and 67.9%, respectively, which were significantly higher than the theoretical values. The same allelic frequencies among the A, B and D genomes were 62.2%, 61.3% and 74.3%, respectively. The lateral roots and root tips of Jing 411 were better than those of their derivative varieties, and the improvement of the traits such as the main root length and dry matter weight of the derived varieties was significant. A total of 35 root traits loci were identified by SNP markers and root traits. The major loci controlling root length traits were carried on 3DL and 5BL, which were associated with SNP markers wsnp_Ex_c1032_1972861 and BS00100708_51, respectively. It can be used for molecular aided selection in Beijing 411 Derivatives. The 26 loci from Beijing 411 had a positive effect on the root traits. Zhongmai 175 and CA0958 carried the most positive effect segments, accounting for 73.1% of the total number of positive effect loci. 【CONCLUSION】 The selection of agronomic traits by aboveground parts of traditional breeding can effectively promote the improvement of underground roots, which is equivalent to the polymerization of genetic fragments of excellent traits. Among Beijing 411 populations, Zhongmai 175 was the most successful variety for backbone genetic improvement. It not only carried more Jing 411 excellent root genes, but also had more major root traits, yield performance and wider adaptability than Jing 411.