Department of Plant Genetics and Breeding/Key Laboratory of Crop Heterosis and Utilization of Ministry of Education/Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
The Key Laboratory of Tropical Fruit Biology of Ministry of Agriculture, The South Subtropical Crops Research Institutes, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524091, China.
Theor Appl Genet. 2016 Jul;129(7):1429-1446. doi: 10.1007/s00122-016-2714-2. Epub 2016 May 2.
QTL mapping based on backcross and RIL populations suggests that epistasis together with partial dominance, over-dominance and their environmental interactions of QTLs play an important role in yield heterosis in upland cotton. A backcross population (BC) was constructed to explore the genetic basis of heterosis in upland cotton (Gossypium hirsutum L.). For yield and yield components, recombinant inbred line (RIL) and BC populations were evaluated simultaneously at three different locations. A total of 35 and 30 quantitative trait loci (QTLs) were detected based on the RILs and BC data, respectively. Six (16.7 %) additive QTLs, 19 (52.8 %) partial dominant QTLs and 11 (30.6 %) over-dominant QTLs were detected by single-locus analysis using composite interval mapping in BC population. QTLs detected for mid-parent heterosis (MPH) were mostly related to those detected in the BC population. No significant correlation was found between marker heterozygosity and performance. It indicated that heterozygosity was not always favorable for performance. Two-locus analysis revealed 46, 25 and 12 QTLs with main effects (M-QTLs), and 55, 63 and 33 QTLs involved in digenic interactions (E-QTLs) were detected for yield and yield components in RIL, BC and MPH, respectively. A large number of M-QTLs and E-QTLs showed QTL by environment interactions (QEs) in three environments. These results suggest that epistasis together with partial dominance, over-dominance and QEs all contribute to yield heterosis in upland cotton.
基于回交和 RIL 群体的 QTL 作图表明，上位性以及 QTL 的部分显性、超显性和环境互作对陆地棉杂种优势具有重要作用。为了探索陆地棉杂种优势的遗传基础，构建了一个回交群体（BC）。在三个不同地点同时评估了重组自交系（RIL）和 BC 群体的产量和产量构成。基于 RIL 和 BC 数据，分别检测到 35 个和 30 个数量性状位点（QTL）。在 BC 群体中，通过复合区间作图的单基因座分析，检测到 6 个（16.7%）加性 QTL、19 个（52.8%）部分显性 QTL 和 11 个（30.6%）超显性 QTL。用于中亲杂种优势（MPH）的 QTL 大多与在 BC 群体中检测到的 QTL 相关。标记杂合性与表现型之间没有显著相关性。这表明杂合性并不总是有利于表现型。二基因座分析分别在 RIL、BC 和 MPH 中检测到 46、25 和 12 个具有主效（M-QTLs）的 QTL，以及 55、63 和 33 个涉及双基因相互作用（E-QTLs）的 QTL，用于产量和产量构成。大量的 M-QTLs 和 E-QTLs 在三个环境中均表现出 QTL 与环境互作（QEs）。这些结果表明，上位性以及部分显性、超显性和 QEs 都对陆地棉的产量杂种优势有贡献。
