370份冰草属种质资源表型多样性分析、综合评价及核心种质构建OA

Using 370 Agropyron germplasms as experimental materials,this study systematically inves-tigated their genetic diversity using 31 phenotypic traits and multiple statistical methods,including coeffi-cient of variation,genetic diversity index,cluster analysis,correlation analysis,and grey relational analy-sis.Additionally,QGA software was employed to simulate and analyze genetic distance,sampling ratio,and clustering algorithms to determine optimal parameters for core germplasm construction.The effective-ness of the core subset was verified through principal component analysis and genetic diversity parameters.Results indicated significant phenotypic differentiation and rich genetic diversity in Agropyron germplasms.Quantitative traits(23 in total,with an average diversity index of 1.867)served as the primary carriers of genetic diversity,with their genetic diversity index was significantly higher than that of qualitative traits(1.328).Phenotypic correlations revealed a"source-sink-flow"coordinated development mechanism:leaves and stems exhibited coordinated growth;spike length was positively correlated with spikelet and flo-ret numbers but negatively correlated with spikelet density,providing a basis for ecological adaptive breed-ing.Cluster analysis categorized the materials into three characteristic germplasm types:Type Ⅰ(24 resources,characterized by tall plants,long roots,and long spikes),Type Ⅱ(123 resources,emphasiz-ing spike and leaf development),and Type Ⅲ(223 resources,with high spikelet density and numerous glume veins).Grey relational analysis identified seven core evaluation indicators:spikelet number,florets per spike,spike width,first rachis internode length,leaf color,leaf sheath length,and second internode stem diameter.Fifteen comprehensively excellent materials(GB3,BB34,MB15,BB55,XB6,MB25,MB32,GB11,MB7,SB55,SB52,BB68,XB3,BB110,XB2)were selected.A core germplasm consist-ing of 92 accessions was constructed using"Mahalanobis distance+deviation sampling+sum of squared deviations+25%sampling ratio."This core subset included all 15 excellent materials,achieving an organic unity of genetic diversity conservation(MD=0,CR=100%)and superior trait screening(VD=41.935%,VR=115.413%).Principal component analysis confirmed high consistency between the core germplasm and the original population in genetic structure(core germplasm cumulative contribution rate:73.014%;original population:64.407%).This study integrates phenotypic diversity analysis,grey relational evalua-tion,and core germplasm construction techniques,providing theoretical basis and material support for the efficient utilization and genetic improvement of Agropyron germplasm resources.