栽培绿豆V1128抗豆象基因定位

Genetic Mapping of Bruchid Resistance Gene in Mungbean V1128

对抗豆象资源中蕴藏的抗豆象基因进行定位,是对其充分利用的前提和基础。本研究通过对抗豆象栽培绿豆V1128和感豆象栽培绿豆冀绿7号杂交形成的F2分离群体进行抗豆象鉴定,分析V1128抗豆象遗传规律;并利用混合群体分离分析法(BSA法)筛选抗感池间的多态性标记,进而利用QTL IciMapping 4.0对V1128抗豆象基因进行染色体定位分析。结果表明, V1128对绿豆象的抗性由具有主效作用的显性单基因控制,暂命名其为"Br3"。在将抗豆象性状作为质量性状的条件下,按照显性单基因的定位方法,将抗豆象基因Br3定位在绿豆染色体5上,位于标记DMB158和VRBR-SSR033(标记VRID5、VRBR-SSR032与VRBR-SSR033的连锁群位置相同)之间,两侧遗传距离分别为4.4cM和5.8cM,所在物理区间约288kb。将抗豆象性状作为数量性状,采用完备区间作图法(ICIM)对种子被害率进行QTL定位,同样在标记DMB158和VRBR-SSR033之间检测到1个主效QTL,其LOD值为38.04,可以解释表型变异(PVE)的71.64%,来自父本V1128的等位基因具有明显减少种子被害率的效应。该研究结果可以为绿豆抗豆象分子标记辅助育种及抗豆象基因Br3的精细定位和克隆提供有用信息。

It is an urgent research topic to map the bruchid resistance gene and to carry out bruchid resistance breeding using molecular marker-assisted method in mungbean.This study was carried out to identify a F2 isolated group formed by the hybrid of a bruchid-resistant cultivar“V1128”and a bruchid-susceptible cultivar“Jilyu 7”,and to analyze the genetic regularity of V1128 in resistance to bruchids.The bulked segregant analysis(BSA)method was used for screening the polymorphic markers.Genetic linkage map construction and quantitative trait locus(QTL)mapping were conducted using software QTL IciMapping 4.0.The results showed that the bruchid resistance of V1128 was controlled by a dominant gene with main effect.According to previous naming rules,the bruchid resistance gene of V1128 was temporarily named as“Br3”.When we treated bruchid-resistance as a quality trait,Br3 was used as a marker for linkage map construction and was positioned between the markers DMB158 and VRBR-SSR033(VRID5,VRBR-SSR032,and VRBR-SSR033 are located at the same map position).The genetic distances of Br3 away from the two markers were 4.4 cM and 5.8 cM,respectively.Br3 was positioned on chromosome 5 in the physical range of about 288 kb.By using the inclusive composite interval mapping(ICIM)to locate the seed damage rate,a main QTL locus with LOD score of 38.04 was identified in the marker intervals from DMB158 to VRBR-SSR033,contributing 71.64%of the observed phenotypic variation.The allele of male parent V1128 had a significant effect on reducing the rate of seed damage.The results can provide useful information for the molecular marker-assisted breeding of mungbean,and the fine localization and cloning of Br3.