title: A dynamic and complex network regulates the heterosis of yield-correlated traits in rapeseed (Brassica napus L.).
abstract: Although much research has been conducted, the genetic architecture of heterosis remains ambiguous. To unravel the genetic architecture of heterosis, a reconstructed F(2) population was produced by random intercross among 202 lines of a double haploid population in rapeseed (Brassica napus L.). Both populations were planted in three environments and 15 yield-correlated traits were measured, and only seed yield and eight yield-correlated traits showed significant mid-parent heterosis, with the mean ranging from 8.7% (branch number) to 31.4% (seed yield). Hundreds of QTL and epistatic interactions were identified for the 15 yield-correlated traits, involving numerous variable loci with moderate effect, genome-wide distribution and obvious hotspots. All kinds of mode-of-inheritance of QTL (additive, A; partial-dominant, PD; full-dominant, D; over-dominant, OD) and epistatic interactions (additive × additive, AA; additive × dominant/dominant × additive, AD/DA; dominant × dominant, DD) were observed and epistasis, especially AA epistasis, seemed to be the major genetic basis of heterosis in rapeseed. Consistent with the low correlation between marker heterozygosity and mid-parent heterosis/hybrid performance, a considerable proportion of dominant and DD epistatic effects were negative, indicating heterozygosity was not always advantageous for heterosis/hybrid performance. The implications of our results on evolution and crop breeding are discussed.
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China.
authors: Jiaqin
authors: J
authors: Shi
authors: Ruiyuan
authors: R
authors: Li
authors: Jun
authors: J
authors: Zou
authors: Yan
authors: Y
authors: Long
authors: Jinling
authors: J
authors: Meng
mesh_terms: D029688:Brassica napus / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D004777:Environment; D004843:Epistasis, Genetic / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D006579:Heterozygote; D006823:Hybrid Vigor / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci