杂种优势是提高作物产量最有效的途径之一，研究控制玉米杂种优势性状的遗传位点对玉米杂交育种具有重要理论和实践意义。本研究通过对全基因组重测序数据分析发现了120,122个高质量InDel和SNP 变异位点，通过这些位点可以将具有不同遗传背景的285份玉米自交系划分为9大类群，包括黄淮海地区两大杂种优势群PA和SPT群。检测PA和SPT群间自交系基因型频率的分布和差异发现1,251个杂种优势候选位点不均匀分布在玉米10条染色体上，其中728个位点与92个已报道的杂种优势相关QTLs一致。基于候选位点，我们对部分黄淮海地区的主栽杂交品种进行了杂合性分析，InDel和SNP结果均表明这些位点的杂合性显著高于其它区域，结果不但验证了本研究获得的候选区域的可靠性，还表明这些候选位点的杂合性已被广泛的运用于育种过程中。
英文摘要:
The heterosis is widely applied for yield increasement in maize, although the underlying genomic mechanism has not well elucidated. Here, we have taken advantages of maize re-sequencing data deposited in NCBI, and more than 120,122 DNA variations of InDel and SNP, were called from 285 diverse inbred lines. Analysis of genetic distances showed population stratification, and nine genetically distinct clusters were grouped, including PA and SPT groups, which were two predominant heterotic groups used in commercial hybrid breeding in Huanhuaihai region. The utility of InDel and SNP variations for performing genome-wide scanning for individuals from PA and SPT groups has found that 1,251 loci have exhibited the significant difference of allele frequency after FST test. Noticeably, 728 newly identified loci have bracketed the 92 previously reported QTL from several previous studies for heterosis. Moreover, we conducted Indel and SNP scanning for a panel of several commercialized hybrids growing in Huanhuaihai region. The results exhibited the significant higher loci heterozgousity near candidate loci, which decreased when span to flanking regions, suggesting that the newly identified heterozgousity has been inadvertently selected during maize heterosis breeding. The results provided the more efficient and targeted use of the genetic loci for hybrid breeding in maize.
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