Mahmood T, Rahman M H, Stringam G R, Raney J P, Good A G
Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Canada.
Genome. 2005 Aug;48(4):755-60. doi: 10.1139/g04-122.
A detailed RFLP map was used to map QTLs associated with seed colour in Brassica juncea using a doubled-haploid population derived from a cross between a black/brown-seeded cultivar and a yellow-seeded breeding line. Segregation analysis suggested that seed colour was under control of 2 unlinked loci with duplicate gene action. However, QTL analysis revealed 3 QTLs, SC-B4, SC-A10 and SC-A6, affecting seed colour. The QTLs were consistent across environments, and individually explained 43%, 31%, and 16%, respectively, and collectively 62% of the phenotypic variation in the population. Digenic interaction analysis showed that closest flanking locus of QTL SC-B4, wg7b6cNM, had strong epistasis with the locus wg5a1a, which is tightly linked to QTL SC-A6. The interaction of these 2 loci explained 27% of the phenotypic variation in the population, while the whole model explained 84%. In a multiple regression model, the effects of QTL SC-A10, as well as its interaction with other loci, were non-significant, whereas the effects of loci wg7b6cNM and wg5a1a and their interaction were significant. Ninety-eight percent of the DH lines carried the expected alleles of loci wg7b6cNM and wg5a1a for seed colour, confirming that only these 2 loci were linked to seed colour in B. juncea. Four additional digenic interactions significantly affected seed colour, and all 5 digenic interactions were consistent across environments.
利用从一个黑/棕色种子品种与一个黄色种子育种系杂交产生的双单倍体群体，构建了一张详细的RFLP图谱，用于定位芥菜中与种子颜色相关的QTL。分离分析表明，种子颜色受2个不连锁位点的控制，具有重复基因作用。然而，QTL分析揭示了3个影响种子颜色的QTL，即SC-B4、SC-A10和SC-A6。这些QTL在不同环境中表现一致，分别解释了群体中表型变异的43%、31%和16%，共同解释了62%。双基因互作分析表明，QTL SC-B4最接近的侧翼位点wg7b6cNM与位点wg5a1a存在强上位性，wg5a1a与QTL SC-A6紧密连锁。这2个位点的互作解释了群体中27%的表型变异，而整个模型解释了84%。在多元回归模型中，QTL SC-A10的效应及其与其他位点的互作不显著，而位点wg7b6cNM和wg5a1a的效应及其互作显著。98%的双单倍体系携带了位点wg7b6cNM和wg5a1a预期的种子颜色等位基因，证实芥菜中只有这2个位点与种子颜色相关。另外4个双基因互作显著影响种子颜色，所有5个双基因互作在不同环境中表现一致。
