A Dynamic and Complex Network Regulates the Heterosis of Yield-Correlated Traits in Rapeseed (Brassica napus L.)

作者：Shi, Jiaqin^*; Li, Ruiyuan; Zou, Jun; Long, Yan; Meng, Jinling

来源：PLos One, 2011, 6(7): e21645.

DOI：10.1371/journal.pone.0021645

• OVERDOMINANT EPISTATIC LOCI
• RECOMBINANT INBRED LINES
• PRIMARY GENETIC-BASIS
• GRAIN-YIELD
• INBREEDING DEPRESSION
• TESTCROSS PROGENIES
• OILSEED RAPE
• HEADING DATE
• CROP YIELD
• RICE

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 x additive, AA; additive x dominant/dominant x additive, AD/DA; dominant x 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.

• 出版日期2011-7-1
• 单位华中农业大学