Peiffer Jason A, Romay Maria C, Gore Michael A, Flint-Garcia Sherry A, Zhang Zhiwu, Millard Mark J, Gardner Candice A C, McMullen Michael D, Holland James B, Bradbury Peter J, Buckler Edward S
Department of Genetics, Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695.
Genetics. 2014 Apr;196(4):1337-56. doi: 10.1534/genetics.113.159152. Epub 2014 Feb 10.
Height is one of the most heritable and easily measured traits in maize (Zea mays L.). Given a pedigree or estimates of the genomic identity-by-state among related plants, height is also accurately predictable. But, mapping alleles explaining natural variation in maize height remains a formidable challenge. To address this challenge, we measured the plant height, ear height, flowering time, and node counts of plants grown in >64,500 plots across 13 environments. These plots contained >7300 inbreds representing most publically available maize inbreds in the United States and families of the maize Nested Association Mapping (NAM) panel. Joint-linkage mapping of quantitative trait loci (QTL), fine mapping in near isogenic lines (NILs), genome-wide association studies (GWAS), and genomic best linear unbiased prediction (GBLUP) were performed. The heritability of maize height was estimated to be >90%. Mapping NAM family-nested QTL revealed the largest explained 2.1 ± 0.9% of height variation. The effects of two tropical alleles at this QTL were independently validated by fine mapping in NIL families. Several significant associations found by GWAS colocalized with established height loci, including brassinosteroid-deficient dwarf1, dwarf plant1, and semi-dwarf2. GBLUP explained >80% of height variation in the panels and outperformed bootstrap aggregation of family-nested QTL models in evaluations of prediction accuracy. These results revealed maize height was under strong genetic control and had a highly polygenic genetic architecture. They also showed that multiple models of genetic architecture differing in polygenicity and effect sizes can plausibly explain a population's variation in maize height, but they may vary in predictive efficacy.
株高是玉米（Zea mays L.）中遗传性最强且最易于测量的性状之一。给定一个系谱或相关植株间基因组状态相同性的估计值，株高也是可以准确预测的。但是，定位解释玉米株高自然变异的等位基因仍然是一项艰巨的挑战。为应对这一挑战，我们测量了在13种环境下超过64500个地块中种植的植株的株高、穗位高、开花时间和节数。这些地块包含了代表美国大多数公开可用玉米自交系的7300多个自交系以及玉米巢式关联作图（NAM）群体的家系。进行了数量性状位点（QTL）的联合连锁作图、近等基因系（NIL）中的精细作图、全基因组关联研究（GWAS）以及基因组最佳线性无偏预测（GBLUP）。玉米株高的遗传力估计超过90%。定位NAM家系嵌套QTL发现，其最大可解释株高变异的2.1±0.9%。通过在NIL家系中的精细作图，独立验证了该QTL上两个热带等位基因的效应。GWAS发现的几个显著关联与已确定的株高基因座共定位，包括油菜素内酯缺乏型矮化1、矮化植株1和半矮化2。GBLUP解释了群体中超过80%的株高变异，并且在预测准确性评估中优于家系嵌套QTL模型的自助聚合。这些结果表明，玉米株高受强大的遗传控制，具有高度多基因的遗传结构。它们还表明，多基因性和效应大小不同的多种遗传结构模型都可以合理地解释群体中玉米株高的变异，但它们在预测效力上可能有所不同。
