大麦4个穗部性状的关联分析

Association analysis of four spike traits in barley

穗部性状是大麦产量和品质的重要决定因素,良好的穗部结构应有一定的穗长基础、适合的小穗密度和每穗小穗数。以137份来源广泛的大麦材料为关联群体,利用224对SSR标记获取群体基因型,在2个环境试点下对穗粒数、小穗密度、小穗数、穗长进行性状观察,利用一般线性模型(GLM)和混合线性模型(MLM)两种模型进行4个穗部性状与SSR标记的关联分析。供试大麦群体的4个穗部性状差异显著,穗粒数与小穗数、穗长与小穗密度显著相关。224对SSR标记共检测出479个等位变异,平均有效等位基因数、Shannon s指数和PIC分别为1.765、0.612和0.327。供试材料的遗传相似系数(GS)变化范围为0.486~0.891,并在GS值为0.580时,将材料分为2个类群。群体结构分析也将供试材料分为2个亚群。GLM分析显示,与穗粒数、小穗密度、小穗数、穗长相关联的标记位点数量分别有33、13、34、6,这些标记遍布大麦7条染色体,单个标记对表型变异的解释率为8.65%~50.08%(P<0.001);MLM分析显示,与上述4个性状相关联的标记位点数量分别为4、3、4、1,这些标记位于大麦1H、2H和4H染色体,单个标记对表型变异的解释率为3.12%~16.95%(P<0.001)。Ind 1003、Ind 2030、Ind 2055、Ind 4012这4个标记在2个环境中都能被2种模型检测到,且同时与穗粒数和小穗数相关联。

Spike traits are important determinants of barley yield and quality.A good spike structure should have a certain spike length,suitable spikelet density and spikelet number per spike.In this study,137 barley materials from a wide range were used as the population for association analysis.A total of 224 pairs of SSR markers were used to analyze the genotype of the population.Under two environmental experiments,grain number per spike,spikelet density,spikelet number per spike and spike length were recorded.General linear model(GLM)and mixed linear model(MLM)models were used to analyze the association between four spike traits and SSR markers.The results showed that there were significant differences among the four spike traits of the tested barley population.Grain number per spike was significantly related to spikelet number per spike,and spike length was significantly related to spikelet density.A total of 479 alleles were detected for SSR markers.The average effective allele number,Shannon s index and PIC were 1.765,0.612 and 0.327,respectively.The genetic similarity coefficient(GS)of the tested materials ranged from 0.486 to 0.891.The barley materials were divided into two groups at GS value level of 0.580.Population structure analysis also divided the materials into two subgroups.The results of GLM analysis showed that there were 33,13,34 and 6 loci associated with grain number per spike,spikelet density,spikelet number per spike and spike length,respectively,and the phenotypic variation explained by a single marker ranged from 8.65%to 50.08%(P<0.001).These markers were located on seven chromosomes of barley.The results of MLM analysis showed that there were 4,3,4 and 1 marker sites associated with the four spike traits described above,respectively.The phenotypic variation explained by a single marker ranged from 3.12%to 16.95%(P<0.001).These markers were located on the chromosome 1H,2H and 4H of barley.The four markers Ind1003,Ind2030,Ind 2055 and Ind 4012,which associated to both grain number per spike and spikelet number per spike,could be detected by two models in two tests.