Maximizing Genetic, Morphological, and Geographic Diversity in a Core Collection of Australian Bermudagrass

Bermudagrasses (Cynodon spp.) are genetically and morphologically diverse warm-season species that are valuable for turf and forage. Diverse accessions of Cynodon are preserved in various germplasm banks in Asia, Europe, and the United States. However, the extent of genetic and ecological diversity within Australia has not been previously explored and characterized. To address this issue, a broad-scale collection of Cynodon germplasm across Australia was recently conducted. A core collection was generated from this resource to optimize its utilization in breeding and research. Genetic diversity of 690 Cynodon accessions was characterized using 16 expressed sequence tag (EST)-simple sequence repeat (SSR) markers. The mean number of alleles generated was 7.44 per marker. Genetic data was combined with passport, ploidy level, morphological, and experimental performance data to generate a core collection using a directed stratified sampling method. The core collection comprised 13% of the source germplasm and captured 96% of the allelic diversity. Redundancy within the core collection was avoided with all accessions representing unique genotypes. This core collection will facilitate the future use of Australian germplasm in Cynodon breeding, genomics, conservation, taxonomy, and phylogeographical research.