普通菜豆根系相关性状的关联分析

幼苗期根系发育对作物的生长发育具有重要作用。利用生长袋纸培系统对324份普通菜豆种质的主根长、根干重、根体积、根表面积等9个根系相关性状进行表型鉴定,并结合覆盖全基因组、有多态性的116对SSR标记,利用MLM（Q+K）模型进行表型和标记的关联分析。表型分析表明,324份材料的9个根系相关性状表型变异丰富,平均变异系数的变动范围是10.09%~37.03%;基因型分析表明,116个多态性SSR标记共检测到919个等位变异位点,每个标记的平均基因多样性指数为0.59,多态性信息含量（PIC）平均值为0.54,显示这些标记具有较高的基因多样性;群体结构分析表明,供试材料分为两个亚群,与普通菜豆起源于两个基因库对应;关联分析结果显示,以P<0.01作为显著条件,共检测到48个显著标记位点,其中有10个位点同时与2个以上性状相关联,有5个位点与前人研究结果一致。研究结果为进一步理解普通菜豆根系的遗传机理提供了理论参考,也为分子标记辅助选择改良普通菜豆根系奠定了基础。

Association Analysis of Root-Related Traits in Common Bean

The root development at seeding stage plays an important role in crop growth and development. In this study, nine root-related traits such as taproot length, root dry weight, root volume and root surface area of 324 common bean accessions were examined by phenotyping using the growth bag paper culture system, and 116 polymorphic SSR (simple sequence repeats) markers covering the whole genome were performed by association analysis. Molecular markers and 9 root traits were analyzed by the program of MLM (mixed linear model) in Tassel 2.1 based on population structure and kinship. The results showed that the 324 common bean accessions were rich in phenotypic variation, and the average coefficient of variation (CV) ranged from 10.09% to 37.03%. Genotype analysis showed that 116 polymorphic SSR markers generated 919 allele loci. The range of genetic diversity index was from 0.0051 to 0.9098 with an average of 0.59. The average PIC (polymorphism information content) was 0.54 with range from 0.0051 to 0.9033. The results indicated that these markers had larger genetic diversity among the alleles in common bean accessions. The population structure analysis indicated that 324 common bean varieties were divided into two subgroups, which were consistent with the theory of common beans originated from two gene banks. Association analysis showed that 48 significant marker loci were detected with P<0.01 as a significant condition. Among these loci, ten marker loci were associated with more than two root traits simultaneously, five marker loci were coincident with previous studies, 43 marker loci were verified as new associated loci. The results provide a theoretical basis for further understandings of the genetic mechanism of roots and provide a basis for improvement of root system by molecular-assisted breeding selection in common bean.