四倍体冰草属种质资源的表型综合评价与核心种质构建OA

Species of the genus Agropyron Gaertn.are not only recognized as premium perennial forages worldwide but also serve as critical exogenous donors for broadening the genetic base and improving the comprehensive traits of wheat through wide hybridization.To promote the efficient utilization of Agropyron germplasm resources,this study investigated 206 accessions of diverse origins(excluding A.mongolicum).Ploidy levels were first identified using flow cytometry in combination with cytological observations.Subsequently,a comprehensive evaluation of tetraploid Agropyron germplasm was performed based on 16 phenotypic traits through diversity,correlation,cluster,and membership function analyses.Finally,the optimal strategy for constructing a tetraploid Agropyron core collection was screened from 384 combinations involving two genetic distances,three sampling methods,eight sampling proportions,and eight clustering methods,followed by a representativeness validation.The results indicated that the tested germplasm consisted of 187 tetraploids,8 diploids,and 11 hexaploids.The coefficient of variation for the 16 phenotypic traits in the tetraploid accessions ranged from 15.78％to 38.26％,with an average of 24.42％.The genetic diversity index ranged from 1.58 to 1.99,with an average of 1.83,indicating high phenotypic diversity.Through systematic comparison,the strategy of"Euclidean distance+multiple cluster priority sampling+15％sampling proportion+single distance method"was identified as the optimal strategy,leading to the construction of a core collection containing 28 accessions.Multi-dimensional validation confirmed that the core collection effectively represents the genetic characteristics and population structure of the initial collection.Five elite germplasm accessions with high comprehensive scores,namely Z559,Z1511,LF112,Z1780 and LF1782,were screened out via subordinate function comprehensive evaluation.All of them were included in the core germplasm collection,which further verified the superiority of the core germplasm.In summary,the tetraploid Agropyron core collection developed in this study provides a reliable representation of the original population,offering a theoretical basis and material foundation for the preservation,evaluation,and genetic improvement of Agropyron germplasm.