Core Germplasm Construction Based on Genetic and Phenotypic Diversity of Buffalograss (Bouteloua dactyloides (Nutt.) Columbus) from the Great Plains of America

Abstract

Buffalograss is a valuable forage and turfgrass species native to the Great Plains of America. Utilization of genetic resources and conservation of germplasm rely on effective methods to differentiate and identify genetic differences quickly and at a relatively low cost. The lack of correlation between DNA marker-based genetic diversity and the geographic distance in buffalograss indicates that the interaction between genotype and environment needs to be evaluated. The objective of this study was to establish a core collection of buffalograss germplasm based on SRAP, then solidify the construction with important phenotypic traits. A total of 143 accessions were collected from 16 regions in 10 states of the U.S. A total of 1033 bands were scored from the 10 combinations of forward and reverse primers, of which 1031 were polymorphic within the accessions. After evaluating multiple clustering approaches, we determined that using symmetric distance (such as DMATCH, SM) in the hierarchical Ward’s method was the best clustering method, resulting in five groups. A least distance stepwise clustering approach using the simple match similarity coefficient was most efficient in creating core collections. Adding the phenotypic information and a final core collection size of 59 accessions was recommended to balance representativeness and diversity. We proposed a reverse power function for the percentage of accessions to be included in a core collection. We started at a high value for small numbers of accessions, and the percentage decreased as the accession number increased. then level off at 10% as the accession number reached 1000 and above.