Comparative analysis of seeded and vegetative biotype buffalograsses based on phylogenetic relationship using ISSRs, SSRs, RAPDs, and SRAPs.

Buffalograss [ Buchloe dactyloides (Nutt.) Englem.] is the only native grass that is being used extensively as a turfgrass in the Great Plains region. Its low-growth habit, drought resistance, and low-maintenance requirement make it attractive as a turfgrass species. Our objective was to obtain an overview on the genetic relatedness among and within seeded and vegetative biotype buffalograsses using inter-simple sequence repeats (ISSRs), random amplified polymorphic DNA (RAPDs), sequence-related amplified polymorphisms (SRAPs), and simple sequence repeats (SSRs) markers that were derived from related species (maize, pearl millet, sorghum, and sugarcane). Twenty individuals per cultivar were genotyped using 30 markers from each marker system. All buffalograss cultivars were uniquely fingerprinted by all four marker systems. Mean genetic similarities were estimated at 0.52, 0.51, 0.62, and 0.57 using SSRs, ISSRs, SRAPs, and RAPDs, respectively. Two main clusters separating the seeded-biotype from the vegetative-biotype cultivars were produced using UPGMA analysis. Further subgroupings were unequivocal. The Mantel test resulted in a very good fit (SRAP=0.92, ISSR=0.90) to good fit (RAPD=0.86, SSR=0.88) of cophenetic values. Comparing the four marker systems to each other, RAPD and SRAP similarity indices were highly correlated ( r=0.73), while Spearman's rank correlation coefficient between RAPDs and SSRs was r=0.24 and between ISSRs and SSRs was r=0.66. A genotype-assignment analytical approach might be useful for cultivar identification and property rights protection. Polymorphic SRAPs were abundant and demonstrated genetic diversity among closely related cultivars.