大豆抗倒伏机理及分子设计育种研究

Lodging is an important agronomical trait in soybean, has obvious negative on the yield, seed quality and mechanical harvesting efficiency. The objective of present study is dissection of the mechanism of lodging resistance and molecular design breeding in soybean. The association population is constructed and genotyped by high-throughput SNP array. Association mapping is used to identified the loci associated lodging have been reported, and detected the new loci associated lodging and related traits (plant height, nodes on main stem, internode length, stem diameter, stem strength, branch number) in soybean. To dissection of the mechanism of lodging resistance, associated regions of lodging and related traits are to be analyzed by bioinformatics, and the candidate genes of lodging related traits will be identified. The co-dominant markers (CAPS and SSR) of lodging are to be developed for molecular design by successive back and self cross with marker-assisted selection. In the end, the elite lines with high lodging resistance will be developed. The results of present study will provide important theoretical basis on soybean molecular design breeding and theoretical guide for the study of lodging resistance in soybean.

本项目在利用大豆重组自交系群体完成的大豆倒伏及相关性状QTL定位和遗传分析的基础上，利用关联分析群体，进一步明确大豆抗倒伏机理，发掘大豆抗倒伏的优异基因位点，开发与抗倒伏紧密连锁的共显性分子标记，并进行抗倒伏分子设计育种。首先，构建关联分析群体，进一步明确大豆倒伏与相关性状（株高，茎杆强度，分枝数，节间长度，主茎节数，茎粗等）的关系；第二，通过关联分析，对已报道的大豆抗倒伏位点进行验证，发掘新的基因位点，优异等位变异及其载体材料；第三，通过对倒伏及相关性状共关联区域的基因进行生物信息学分析，获取与倒伏相关性状的候选基因，进而明确大豆抗倒伏的机理；第四，根根据抗倒伏关联位点，开发共显性分子标记，进行大豆抗倒伏分子设计育种，获取聚合多个抗倒伏基因位点的高抗倒伏大豆材料。研究结果可为大豆抗倒伏品种改良提供理论依据，也可为其它性状改良和分子设计育种提供参考和理论依据。

倒伏是大豆生产中一个普遍存在的问题，是大豆高产稳产和优质的主要限制因素之一。研究表明，大豆倒伏主要为茎秆倾斜或弯曲引起植株歪倒，大豆倒伏与株高（PH）、茎粗（SD）、主茎节数（NN）、节间长度（IL）、分枝数（BN）、茎秆强度（SS）及根重（RW）显著相关。多元回归分析表明，株高、根重、分枝数和茎杆强度是影响大豆倒伏的主要因素，对大豆倒伏的解释率分别为37.04%,18.40%，5.12%和1.53%。根据倒伏及相关性状共关联区域关联区基因注释，查找与分枝数，节间长度，主茎节数，株高，根长，根重，茎粗，茎杆强度相关的基因，在关联区域获取23个相关的基因。通过分子设计育种，创制高抗倒伏材料21份。本研究表明，大豆倒伏是多个相关性状与环境共同作用的结果，所发掘的抗倒伏关联位点，是倒伏相关性状基因位点，通过改良倒伏相关性状，可有效提高大豆的抗倒性。本研究对大豆倒伏性进行了全面和深入的剖析，在分子水平解析了大豆倒伏与相关性状的关系，为进一步阐明大豆抗倒伏机理奠定了基础。