基于桃谱系分析亲本选择与重要经济性状基因挖掘

桃是我国重要的落叶果树之一，栽培面积占世界总量的50%以上。作为多年生经济作物，桃童期长，果实表型鉴定周期长，遗传改良难度大，成本投入高。迄今，定位的QTL精度差、不同群体间重复率低，难以用于分子标记辅助选种，仍依靠经验和对大量后代单株的选择进行遗传改良。如何利用现代分子育种技术，解决传统育种面临的瓶颈，建立高效、科学和系统的遗传改良体系是亟待解决的科学和产业问题。鉴于此，本项目前期建立了高密度的SSR荧光标记（300kb/标记）技术体系和亲本基因分型数据库，获得了多态性的分子标记；构建和筛选了涵盖桃重要目标性状亲本的谱系组合。在此基础上，拟继续开展基于谱系分析QTL定位和基于多代谱系的优势区段选择，精细定位和克隆目标质量性状和主效QTL位点的基因，建立分子辅助选种体系。本项目的顺利开展可为分子设计育种、多性状聚合育种、亲本选择以及重要经济性状形成的遗传机制解析奠定基础。

Peach (Prunus persica) is one of the most important deciduous fruit crops in China, which account for more than 50% cultivated area of the world. As a woody perennial plant, peach has long juvenility phase and need 2~3 years for fruiting, increasing the costs and generation of genetic improvement. To update, few QTL have been adopted by breeders for marker-assisted breeding due to low mapping accuracy and specific occurrence in only one population. Traditional breeding strategy is depending on experience and massive offspring selection. How to use the modern molecular breeding technique to overcome the bottleneck of conventional breeding system is urgent and necessary. Establishing the most effective selection and breeding approach can help to solve the scientific and industrial problem for peach. Using populations of multiple families had superior advantages over single mapping population. In this proposal, high density (300 kb per marker) SSR-CE-based detection system and genotyping database for core parents were developed, which generating polymorphism markers. In addition, populations of multiple families were constructed and selected covering desired traits and breeding goals. Further, quality trait and major QTL are proceeded for fine mapping and cloning using multi-pedigree and elite region is selected using multi-generation pedigree reconstruction, which enable to use marker assisted breeding in peach. This proposal has perspective for molecular design breeding, aggregating the elite allele of genes, crossing parents matching, and ultimately elucidate the genetic basis for important traits.