大麦苗期根系和茎叶性状的QTL定位分析

QTL Mapping of Root and Shoot Traits at Seedling Stage in Barley

以耐湿大麦品种泰兴9425与湿害敏感品种Franklin构建的DH系及亲本为材料,在湿害胁迫条件下,考察了大麦苗期与耐湿性相关的根长、根鲜质量、根干质量、茎叶鲜质量和茎叶干质量,各性状均表现为连续分布,且都存在一定数量的双向超亲遗传类型,为多基因控制的数量性状。结合已构建的分子连锁图谱,采用Windows QTL Cartog-rapher 2.5软件中的复合区间作图法进行QTL定位分析。5个根系及茎叶性状共检测到13个QTL,除第2、5染色体外,其他染色体上均有分布,LOD值为2.59-3.83,对表型变异的解释率为10.99%-20.7%。其中最大根长检测到2个QTL,控制根系鲜质量和干质量的QTL分别为2,3个,与茎叶鲜质量和干质量相关的均为3个。在第6、7染色体存在QTL成簇分布的现象,表明可能存在一因多效或QTL紧密连锁的情况。为大麦苗期耐湿相关根系性状的分子标记辅助选择育种奠定了基础。

A population of DH was constructed,which derived from a cross between Taixing 9425 with water-logging tolerance and Franklin which is susceptible to waterlogging. The five characters associated with waterlogging tolerance including maximum root length,root fresh weight,root dry weight,shoot fresh weight,shoot dry weight were investigated under water stress. Transgressive segregations for all traits were observed in the population, and their frequencies were showed a continuous distribution. The characters were controlled by multi-genes with major effects, and minor modifiers. Based on the linkage map,the composite interval mapping approach of QTL Cartographer 2. 5 was used to detect the QTL for these traits. A total of 13 QTL associated with root and shoot traits were mapped on all chromosomes except 2 and 3. All QTL were responsible for interpreting 10. 99% -20. 7%,and the range of LOD were 2. 59-3. 83. Among these QTL,2 QTL controlling maximum root length,2 QTL controlling root fresh weight, 3 QTL controlling root dry weight,3 QTL controlling shoot fresh weight and 3 QTL controlling shoot dry weight were detected. Tightly linked QTL regions on chromosome 6 and 7 were identified,which suggested the existence of pleio-tropic or genetic linkage. The above result played a vital role in marker assisted selection and fine mapping of QTL associated with root and waterlogging tolerance.