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    • Keywords


      heterosis; empirical bayes; NCIII design; recombinant inbred line; quantitative trait locus.

    • Abstract


      North Carolina design III (NCIII) is one of the most powerful and widely used mating designs for understanding the genetic basis of heterosis. However, the quantitative trait mapping (QTL) conducted in previous studies with this design was mainly based on analysis of variance (ANOVA), composite interval or multiple interval mapping methods. These methodologies could not investigate all kinds of genetic effects, especially epistatic effects, simultaneously on the whole genome. In this study, with a statistical method for mapping epistatic QTL associated with heterosis using the recombinant inbred line (RIL)-based NCIII design, we conducted QTL mapping for nine agronomic traits of two elite hybrids to characterize the mode of gene action contributing to heterosis on a whole genomewide scale. In total, 23 main-effect QTL (M-QTL) and 23 digenic interactions in IJ (indica × japonica) hybrids, 11 M-QTL and 82 digenic interactions in II (indica × indica) hybrid QTLs were identified in the present study. The variation explained by individual M-QTL or interactions ranged from 2.3 to 11.0%. The number of digenic interactions and the total variation explained by interactions of each trait were larger than those of M-QTL. The augmented genetic effect ratio of most M-QTL and digenic interactions in (L1–L2) data of two backcross populations (L1 and L2) showed complete dominance or overdominance, and in (L1 + L2) data showed an additive effect. Our results indicated that the dominance, overdominance and epistatic effect were important in conditioning the genetic basis of heterosis of the two elite hybrids. The relative contributions of the genetic components varied with traits and the genetic basis of the two hybrids was different.

    • Author Affiliations


      Lanzhi Li1 2 Xiaohong He3 Hongyan Zhang1 Zhiming Wang1 Congwei Sun1 Tongmin Mou4 Xinqi Li5 Yuanming Zhang3 Zhongli Hu2

      1. Hunan Provincial Key Laboratory for Biology and Control of Plant Disease and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha 410128, People’s Republic of China
      2. State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan 430072, People’s Republic of China
      3. Section on Statistical Genomics, State Key Laboratory of Crop Genetics and Germplasm Enhancement/Chinese National Center for Soybean Improvement, College of Agriculture, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
      4. National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, People’s Republic of China
      5. Department of Breeding, China National Hybrid Rice Research and Development Center, Changsha 410125, People’s Republic of China
    • Dates

  • Journal of Genetics | News

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      Posted on July 25, 2019

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