Li Hongjian, Yang Qingsong, Fan Nannan, Zhang Ming, Zhai Huijie, Ni Zhongfu, Zhang Yirong
State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis Utilization (MOE), China Agricultural University, Beijing, 100193, China.
National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
BMC Genet. 2017 Apr 17;18(1):36. doi: 10.1186/s12863-017-0503-9.
Plant height (PH) and ear height (EH) are two important agronomic traits in maize selection breeding. F hybrid exhibit significant heterosis for PH and EH as compared to their parental inbred lines. To understand the genetic basis of heterosis controlling PH and EH, we conducted quantitative trait locus (QTL) analysis using a recombinant inbreed line (RIL) based design III population derived from the elite maize hybrid Zhengdan 958 in five environments.
A total of 14 environmentally stable QTLs were identified, and the number of QTLs for Z and Z populations was six and eight, respectively. Notably, all the eight environmentally stable QTLs for Z were characterized by overdominance effect (OD), suggesting that overdominant QTLs were the most important contributors to heterosis for PH and EH. Furthermore, 14 environmentally stable QTLs were anchored on six genomic regions, among which four are trait-specific QTLs, suggesting that the genetic basis for PH and EH is partially different. Additionally, qPH.A-1.3, modifying about 10 centimeters of PH, was further validated in backcross populations.
The genetic basis for PH and EH is partially different, and overdominant QTLs are important factors for heterosis of PH and EH. A major QTL qPH.A-1.3 may be a desired target for genetic improvement of maize plant height.
株高（PH）和穗位高（EH）是玉米选育中的两个重要农艺性状。与亲本自交系相比，F1杂交种在株高和穗位高上表现出显著的杂种优势。为了解控制株高和穗位高杂种优势的遗传基础，我们利用来自优良玉米杂交种郑单958的基于重组自交系（RIL）的设计III群体，在五个环境中进行了数量性状位点（QTL）分析。
共鉴定出14个环境稳定的QTL，其中Z群体和Z群体的QTL数量分别为6个和8个。值得注意的是，Z群体的所有8个环境稳定QTL均表现为超显性效应（OD），这表明超显性QTL是株高和穗位高杂种优势的最重要贡献者。此外，14个环境稳定的QTL定位在6个基因组区域，其中4个是性状特异性QTL，这表明株高和穗位高的遗传基础部分不同。此外，qPH.A - 1.3可使株高改变约10厘米，在回交群体中得到了进一步验证。
株高和穗位高的遗传基础部分不同，超显性QTL是株高和穗位高杂种优势的重要因素。一个主要的QTL qPH.A - 1.3可能是玉米株高遗传改良的理想目标。
