State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China.
Plant Biotechnol J. 2020 Jan;18(1):185-194. doi: 10.1111/pbi.13186. Epub 2019 Jun 27.
Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear in many crops. Here, we present a large-scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield-related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete-incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the major causes of strong heterosis in these hybrids. Follow-up studies for 17 heterotic loci in an independent experiment using 2225 F individuals suggest most heterotic effects are roughly stable between environments with a small variation. Candidate gene analysis for one major heterotic locus (ub3) in maize implies that there may exist some common genes contributing to crop heterosis. These results provide a community resource for genetics studies in maize and new implications for heterosis in plants.
杂种优势，或杂种优势，是植物遗传学中的主要现象，是作物杂交育种的基础，但许多作物中杂种优势的因果基因座和基因仍不清楚。在这里，我们使用三个优秀玉米杂交种的 5360 个后代进行了大规模的遗传分析，确定了 628 个与 19 个与产量相关的性状相关的基因座，具有相对较高的映射分辨率。对 628 个基因座的杂种优势模式研究表明，许多基因座主要具有杂合基因型的完全不完全显性（主要）或超显性效应（次要），并且来自双亲的有利等位基因的比例几乎相等，是这些杂种中强杂种优势的主要原因。在使用 2225 个 F 个体的独立实验中对 17 个杂种优势基因座的后续研究表明，大多数杂种优势效应在环境之间大致稳定，变化很小。对玉米中一个主要杂种优势基因座（ub3）的候选基因分析表明，可能存在一些共同的基因有助于作物杂种优势。这些结果为玉米的遗传学研究提供了一个社区资源，并为植物杂种优势提供了新的启示。
