水稻保持系58B高柱头外露率的QTL定位

QTL Mapping of High Percentage of Stigma Exsertion in Rice Maintainer Line 58B

利用籼型三系保持系58B(高柱头总外露率,达85.47%)作父本与粳稻日本晴(低柱头总外露率,仅3.33%)杂交构建F2代分离群体。利用亲本间有多态性的113对SSR标记对F2代群体各单株进行基因型分析,同时对柱头双边外露率、柱头单边外露率和柱头总外露率3种性状进行了表型鉴定,并对上述性状进行QTL定位。结果表明,柱头外露率各性状在F2群体中均呈连续分布,表现为由多基因控制的数量性状;共检测到13个与柱头外露率相关的QTL,分布于第1、2、3、4、5、7、8、10和12染色体上,柱头双边外露率、柱头单边外露率和柱头总外露率分别检测到4、5和4个QTL。除qDPES8之外,其余12个QTL的增效等位基因均来自高柱头外露父本58B。其中,柱头双边外露率位点qDPES1和柱头单边外露率位点qSPES1均定位在第1染色体的RM449-RM466区间内,分别解释了14.15%和9.56%的表型变异率,此位点可能是新的QTL位点,为进一步克隆和解析新柱头外露率QTL的基因功能奠定了基础。

An F2 population was established from the cross between 58 B(an indica rice maintainer line with stigma exsertion rate as high as 85.47%) as the male and Nipponbare(a japonica rice variety with only 3.33% of stigma exsertion rate). The genotype of the single plants in the F2 population was analyzed with 113 SSR markers showing polymorphism between the parents. In the meantime, the phenotypes of the plants were also identified and the QTLs were mapped in three traits of the percentage of single stigma exsertion(SPES), percentage of double stigma exsertion(DPES) and percentage of total stigma exsertion(PES). The results showed that all of three traits exhibited continuous distribution in F2 population, indicating that they all belong to quantitative traits controlled by multiple genes. A total of 13 QTLs related to the percentage of stigma exsertion were detected on chromosomes 1,2,3,4,5,7,8,10 and 12. Among them, four, five and four QTLs were for DPES, SPES and PES, respectively. Except for qDPES8, the rest of all QTLs with enhancing effect derived from 58 B with the higher percentage of stigma exsertion. Two major QTLs of qDPES1 and qSPES1, explaining 14.15% and 9.56% of variation in phenotype, respectively, were both located in the same interval of RM449-RM446 on chromosome 1, suggesting that it might be a new site and providing a good basis for cloning and analyzing new gene functions of QTLs related to percentage of stigma exsertion.