桃垂枝性状的精细定位及关键基因的解析

Peach is facing the challenges of labor shortage. One of the world's breeding objectives was to breed reasonable structure trees which could meet various cultivation modes, simplify pruning methods and reduce labor costs. Although physiological, biochemical and related genes of different tree structure of peach have been studied,the progress of genetic improvement and utilization in weeping peach was slow. Weeping peach was difficult to identify at seedling stage. To establish molecular assisted selection system for target traits and genetic improvement exactly, we need to find the genetic mechanism of the formation of weeping traits and fine map the weeping gene of peach. In this study, F2 population with well-separated traits with 163 seedlings was used as experimental material and pl was located in LG4 by BSA-seq.Bioinformatics analysis in the pl region predicted a novel mechanism underling weeping traits comparing to the known report.Molecular markers were developed on a large scale on the basis of preliminary location. After screening and fine mapping, candidate genes for weeping branch traits were obtained. Effective markers for marker assisted selection (MAS) and the key gene of weeping branch will be discovered. The moleculer mechanism of weeping traits was analyzed for targeted breeding of weeping ornamental peach and rootstock.

随着劳动力匮乏，选育结构合理、满足各种栽培模式的树型，简化修剪方式，减少人工成本是世界桃育种目标之一。桃树型虽然开展了生理生化和相关基因的研究，但垂枝桃的遗传改良和利用进展缓慢。桃的垂枝性状很难实现早期表型鉴定，明确垂枝性状形成的遗传机制并对桃垂枝基因进行精细定位，是建立垂枝性状分子辅助选种体系和遗传改良的前提。为了挖掘控制桃垂枝性状的关键基因，本研究前期利用163株性状分离良好的F2群体为试验材料，通过BSA重测序将pl初定位于第4连锁群。生物信息学预测桃垂枝的分子机制可能有别于已经报道的果树。本项目继续立足于隐性遗传的桃垂枝性状，大规模分子标记开发筛选后进行精细定位，对垂枝性状进行候选基因的挖掘。预期结果是开发有效的MAS标记，明确垂枝性状的关键基因，为有目标的选育垂枝观赏桃和砧木品种奠定基础。

垂枝桃作为桃的一个变种，枝条下垂不仅具有观赏价值，且其基因的挖掘和机理的发现为开发特异的树型，研究植物生长内在规律打下基础。垂枝桃虽然机理方面开展了生理生化和相关基因的研究，但垂枝桃的遗传改良和利用进展缓慢。桃的垂枝性状很难实现早期表型鉴定，明确垂枝性状形成的遗传机制并对桃垂枝基因进行精细定位，是建立垂枝性状分子辅助选种体系和遗传改良的前提。本研究前期利用F2群体为试验材料，通过BSA重测序将pl初定位于第4连锁群。通过本项目实施，对pl位点进行了精细定位，将其缩小到1M以内，并且筛选出10个候选基因，获得一个KASP分子标记，且认为生长素在垂枝性状发育过程中起重要作用，为后期进一步有目标的开展选育垂枝观赏桃和砧木品种奠定基础。

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