玉米穗型和粒型性状的GWAS及其关联位点驯化和改良分析
玉米的理想穗型和粒型是提升玉米产量的关键。本研究以32份大刍草、68份玉米地方品种和来源广泛的294份玉米自交系为材料，在对294份玉米自交系进行简化基因组测序的基础上，采用GWAS方法对11个玉米穗型和粒型性状进行关联分析。结果发现，11个性状共检测到44个关联的SNP位点，其中28个位点与6个穗型性状相关联，16个位点与3个粒型性状相关联。为了了解这些关联位点是否经历驯化和人工选择，本研究进一步整合32份大刍草和68份地方品种相应位点的序列数据，44个关联位点中共发现29个SNP在3类群体间共有，通过Fisher的精确检验发现7个SNP的等位基因频率在大刍草到地方品种中发生了显著变化，14个SNP的等位基因频率在地方品种到自交系中发生了显著变化，3个SNP的等位基因频率则在大刍草到地方品种以及地方品种到自交系中均发生了显著变化，表明这些位点可能经历了驯化或/和人工改良。研究结果为进一步挖掘穗型和粒型相关候选基因及发展功能分子标记奠定了基础。
英文摘要:
The ideal ear and kernel type of maize are the key to improve maize yield. In this study, 32 teosintes, 68 landraces and 294 inbred lines from a wide range of sources were used as materials. Based on the simplified genome sequencing of 294 maize inbred lines, 11 ear- and kernel-related traits were analyzed by GWAS. The results showed that a total of 44 SNP loci were detected for 11 traits, of which 28 loci were associated with 6 ear-related traits and 16 loci were associated with 3 kernel-related traits. In order to understand whether these associated sites through domestication and improvement, we further integrated the associated loci with sequence data of 32 teosintes and 68 landraces. It is found that a total of 29 SNP shared among the three populations. By Fisher’s exact test, it is found that the allele frequency of 7 SNPs had significant difference between teosinte and landrace, that of 14 SNPs had significant difference between landrace and inbred line, and that of 3 SNPs had significant difference among teosinte, landrace and inbred line. The result suggested that these loci might undergo the domestication or/and artificial improvement in the history of corn evolution. The results laid a foundation for further excavation of candidate genes related to ear and kernel of maize and development of functional molecular markers.
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