Rapeseed as a model to analyse `fixed heterosis` in allopolyploid plants

近缘物种通过结合它们的基因组(异源多倍体)进行的自发杂交在植物进化中发挥了重要作用。异源多倍体成功的一个主要原因是它们的同源染色体上的基因之间存在有利的相互作用(‘固定的’杂种优势)。固定的杂种优势在二倍体物种中可能也很重要，因为即使在许多二倍体物种中，大的基因组片段也是重复的。油菜(AACC基因组)是一个非常适合分析固定杂种优势的模式系统，因为人工‘再合成’系可以很容易地从二倍体亲本萝卜油菜(AA)和甘蓝(CC)中培育出来。因此，将产生一种在等位基因贡献上完全平衡的材料，但在杂合度(纯合与杂合)、倍性(二倍体与四倍体)和基因组多样性(同源四倍体与异源四倍体)方面存在差异。在本材料中，将分析多倍体、由于杂合性而产生的‘固定’杂种优势和‘经典’杂种优势在营养生物量生产中的重要性。这份材料将为详细分析‘经典’和‘固定’杂种优势的分子、生化和生理原因提供独特的可能性。

The spontaneous hybridisation of related species by combining their genomes (allopolyploidy) has played a prominent role in plant evolution. A main reason for the success of allopolyploids are the favourable interactions between genes on their homeologous chromosomes ('fixed' heterosis). Fixed heterosis is probably also important in diploid species because even in many diploids large genome segments are duplicated. Rapeseed (AACC genome) is a very suitable model system to analyse 'fixed' heterosis because artificial 'resynthesized' lines can be easily developed from the diploid parental species turnip rapeseed (AA) and cabbage (CC). Therefore a material will be created, which is completely balanced in the allelic contributions, but differs in the amount of heterozygosity (homozygous vs. heterozygous), ploidy (diploid vs. tetraploid) and genomic diversity (autotetraploid vs. allotetraploid). In this material, the importance of polyploidy, 'fixed' heterosis and 'classical' heterosis due to heterozygosity will be analysed phenotypically for vegetative biomass production. This material will provide unique possibilities for a detailed analysis of the molecular, biochemical and physiological causes of 'classical' and 'fixed' heterosis.