DNA analysis of turfgrass genetic diversity

Turfgrasses constitute an heterogeneous group of species differing widely in reproductive strategy, genome organization, and evolutionary history. Cultivars derived from vegetative propagation or from apomictic or self-pollinated species can be homogeneous at the genetic level, exhibiting little genetic variation. Alternatively, cultivars with an outcrossing breeding system can be genetically heterogeneous, such as those from open-pollinated seeded species. A careful study of the degree and distribution of turfgrass genetic variation is therefore essential for the efficient selection of superior plant material for breeding, an adequate management of genetic resources, and the effective preservation of biodiversity. An array of molecular techniques have targeted nucleic acids to evaluate molecular diversity at the species, population, and within-population levels. These techniques have only recently been applied to the breeding and management of turfgrass germplasm. Using the hybridization and amplification of nucleic acids, DNA profiling techniques have established patterns of genetic variation at the species level in grass systematics, and at the subspecies level in the study of natural populations, breeding lines, cultivars, and accessions. In some eases, chromosome analysis by now cytometry and genomic in situ hybridization have notably complemented the use of nucleic acid markers. DNA profiling techniques have also assessed the genetic stability of cultivars and the appearance of off-types, and have provided molecular estimates of turfgrass evolution. The review of current efforts to evaluate turfgrass genetic diversity clearly indicates that the application of the tools of genome analysis to the study of germplasm diversity may finally unlock the genetic potential of Mild and cultivated turfgrass resources.