菊花托桂性状的遗传解析与分子标记定位

Chrysanthemum is among the traditional flowers in China and the four famous cut-flowers in the world. Anemone-typed cultivars of chrysanthemum possess higher ornamental and commercial values, which have now become an important breeding target in chrysanthemum breeding programs. However, little information has been known regarding the inheritance pattern of or molecular markers for anemone-related traits of chrysanthemum thus far. In this study, we investigated the variation of anemone-related traits of 100 representative cultivars of anemone-typed chrysanthemum and attempted to set up the quantitative evaluation system of anemone-related traits of chrysanthemum. Then we dissected the inheritance pattern of anemone-related traits with combining ability analysis and diallel crosses, and calculated the pairs and effects of major genes controlling anemone-related traits with the mixed inheritance model of major gene plus polygene. Thirdly, genetic mapping and quantitative trait loci analysis were applied to detect the major gene for anemone-related traits, and the 3-year anemone-related traits of F1 mapping population and QTL conjoint analysis by employing QTLNetwork software were further exploited to detect the epistatic effects between QTLs and between QTL and environments (years). Finally, we tried to develop the molecular markers tightly linked with anemone-type using bulked segregation analysis (BSA) method. The dissection of the quantitative inheritance pattern of anemone-related traits of chrysanthemum and the achievement of the anemone-type tightly-linked molecular markers will lay an important foundation for detection of genes determining anemone-related traits of chrysanthemum and will be of great theoretical and practical significance for directive breeding for new cultivars with desirable anemone type.

菊花是我国传统名花和世界四大切花之一。托桂型品种具有更高的观赏与经济价值，现已成为菊花的重要育种目标。但有关菊花托桂性状遗传机制和分子标记研究还鲜有报道。本项目拟调查100个代表性托桂型菊花品种托桂性状的遗传变异，建立菊花托桂性状的量化评价体系；利用托桂差异品种进行不完全双列杂交设计，通过配合力分析和主基因+多基因混合遗传模型剖析菊花托桂性状的遗传特性；通过连锁作图和QTL定位，挖掘控制菊花托桂性状的主效QTL，并利用连续3年托桂表型数据和基于混合线性遗传模型的QTL联合分析，深度解析控制菊花托桂性状的QTL间及QTL与环境间的上位性互作效应；最后，利用集团分离分析法挖掘与菊花托桂型连锁的分子标记。项目实施将从数量遗传学角度揭示菊花托桂性状的遗传特性，获得托桂型连锁的分子标记，为菊花托桂性状相关基因发掘奠定基础，对定向培育托桂型菊花新品种具有重要理论和实践意义。

菊花是我国传统名花和世界四大切花之一，在园林花卉产业具有重要地位。托桂花型品种具有更高的观赏和经济价值，是菊花育种的重要目标性状。目前，鲜见菊花托桂性状的遗传机制和分子标记研究。本项目在调查托桂菊花品种花器性状的基础上，建立了托桂性状的五级量化评价体系，筛选出优异托桂菊花品种；通过12个托桂相关性状和238个SRAP分子标记多态性位点的UPGMA聚类和主成分分析，明确了67份托桂品种的亲缘关系和遗传多样性水平，为后期杂交亲本选配奠定重要基础。通过两个杂交F1代托桂相关性状的混合遗传分析，发现最深羽裂长、管状花宽主要有两对表现为加性-显性-上位性效应的主基因控制，但托桂性状的主基因效应和遗传力在不同遗传背景中差异较大。另外，比较分析了同一母本或父本的不同杂交后代托桂花型分离比例，发现托桂花型具有显著的母性遗传效应。利用SSR和SRAP等分子标记建立了托桂差异菊花品种‘南农雪峰’（托桂）和‘蒙白’（非托桂）的连锁遗传图谱，平均图谱间距分别为9.9cM和11.2cM；利用复合区间作图法定位到20个托桂性状主效QTL，其中6个QTL在多个环境种表现稳定；基于混合线性遗传模型的复合区间作图法定位到16个上位性QTL；单个加性QTL和上位性QTL的表型变异贡献率分别为6.34～11.86% 和3.69%～13.63%，说明加性和上位性效应共同决定托桂性状的遗传基础。最后，通过BSA方法在‘南农雪峰’（托桂）ב蒙白’（非托桂）F1群体开发出一个与菊花托桂花型紧密连锁的SRAP-SCAR分子标记，连锁距离为7.5cM。研究结果揭示了菊花托桂性状的复杂数量遗传机制，获得了托桂花型紧密连锁的分子标记，为后期托桂花型相关基因挖掘和分子标记辅助育种研究奠定重要基础。共计发表SCI论文3篇、核心期刊论文2篇，获国家发明专利1项，培养研究生6名。相关成果获华耐园艺科技奖（2014）。