Core Germplasm Construction Based On Phenotypic And Genetic Diversity Of Buchloe Dactyloides (Nutt.) Engelm

Buffalo grass(Buchloe dactyloides)is a warm-season lawn grass native to the the Great Plains of America.Due to the large scale of buffalo grass resources,the high repeatability of genetic diversity makes genetic research and breeding difficult.The construction of core germplasm can overcome and alleviate the difficulties and pressures caused by the large scale of resources,making it possible to carry out further research on germplasm resources.However,only using phenotypic and molecular marker data to construct core germplasm is likely to omit important target trait information,which affects the accuracy of core germplasm construction and evaluation.There are few studies on the genetic diversity analysis of bison grass and the construction of core germplasm based on phenotype and molecular data.This study explored the best method to construct the core collection of buffalo grass phenotype based on different population sampling size,genetic distance,systematic clustering method and sampling method.Based on SRAP molecular marker data,the evaluation parameter values of admixture-prioritized clustering and Least distance stepwise sampling strategy were compared based on different genetic distance and genetic similarity coefficient.Finally,the phenotypic and molecular data were integrated to establish a core population containing 68 germplasm materials.The main conclusions of the study are as follows:(1)We use 34 female buffalograss germplasm as test material,analyze 10 phenotypic traits.The result shows that 25% based on Euclidean distance,using the multiple clustering deviation sampling method is the best sampling strategy for constructing the primary core collection of buffalograss.The shortest distance method,intermediate distance method and center of gravity method were used to construct the clustering method.Based on phenotypic traits,a primary female core collection of buffalograss containing 8 female germplasm resources was established.(2)We use 41 male buffalograss germplasm as test material,analyze 11 phenotypic traits.The result shows that 20% based on Euclidean distance,using the multiple clustering deviation sampling method is the best sampling strategy for constructing the primary core collection of buffalograss.The shortest distance method was used to construct the clustering method.Based on phenotypic traits,a primary male core collection of buffalograss containing 8 male germplasm resources was established.(3)SRAP molecular marker analysis was carried out on 143 genetic materials,and 1033 bands were selected from 10 primer combinations,with polymorphism of 99.8%.The evaluation results of clustering methods show that the symmetric distances(such as DMATCH and SM)are the best in Ward’s clustering methods,and all genetic materials can be divided into five groups.(4)Based on the evaluation parameters of SRAP molecular marker data,various quality construction schemes were compared,and it was found that SM similarity coefficient and LDSS method were more suitable methods to construct bison grass core germplasm.Under the proportion of 40%,the genetic information of all the genetic materials of buffalo grass could be retained as much as possible,and the core germplasm containing 57 buffalo grass germplasm materials was established.The three-dimensional sample distribution map and the two-dimensional scatter map was established for testing.It was confirmed that the constructed core population containing 68 germplasm materials had balanced representativeness and diversity.To a certain extent,this kind of mass energy represents all the original resources,which is helpful for the full development and utilization of the following uffalo grass germplasm resources.