尽管玉米基因组中存在较多与基因紧密连锁的插入/缺失（InDel）及大片段有无变异（PAV）区域，但是这些功能性结构变异区对杂种优势的作用尚不明确。本项目拟通过全新的三重测交（TTC）交配设计对200株较高遗传分辨率intermated B73 x Mo17（IBM）重组自交系构建其与亲本B73、Mo17及F1杂交的三个测交群体，利用已发展的500个功能性InDel/PAV区域分子标记，结合播种后第21天苗期生物质相关性状（第三片展开叶的叶长、叶宽、叶面积及地上部分干物质重）两年三点的表型数据对目标性状杂种优势位点进行数量性状位点（QTL）定位，明确生物质相关性状杂种优势的主效位点，分析生物质相关性状杂种优势的遗传效应，探索功能性InDel/PAV结构变异与杂种优势的关系，以期从基因组结构变异角度为杂种优势遗传机理的阐明提供新补充。

Maize (Zea mays L.) resequencing results have exhibited that the pervasive functional insert/deletion (InDel) and presence-absence variation (PAV), which reside in or proximity to a function gene, were scattered in the whole genome。However, the implications of functional InDel/PAV structural variation for heterosis remain unknown. Our previous studies have developed around 500 markers physically linked with the functional InDel/PAV variation by calling an effective depth of ⅹ50 coverage of B73 and Mo17 next generation sequencing datasets. Also some of these markers have been mapping on 10 maize linkages with the intermated B73 x Mo17 (IBM) recombinant inbred line (RIL) population. Here, we propose a serial genetic experiments to elucidate the potential roles of functional InDel/PAV in maize seedling heterosis using the triple testcross(TTC) design and a IBM population of 200 RILs crossed with both parents (B73 and Mo17)and their F1, respectively. The four biomass-related traits of these three populations at seedling stage of 21 days after planting(DAP) will be measured in three locations for two years, which include length of 3th leaf fully expanded(LFE), width of 3th LFE, area of 3th LFE and total aerial dry weight. The functional InDel/PAV responsible for heterosis of biomass-related traits will be identified using quantitative trait loci (QTL) detection methods. Subsequently, the genes resided in or proximity to the significant QTL will be under further investigation. The genetic relationships between the functional InDel/PAV variation and seedling heterosis will be established in this proposal, and the results are expected to have a positive impact on heterosis breeding efforts.