GENETIC CHARACTERIZATION OF HETEROGENOUS PLANT POPULATIONS

Department of Agronomy, The Pennsylvania State University, University Park, PA 16802

Genetically characterizing plant populations is important for many plant scientists, including plant breeders and ecologists. Grass breeders not only have to show their cultivars are distinct for purposes of plant variety protection or seed certification but also may soon need to characterize their cultivars to accommodate new laws governing essentially derived variety (EDV). Restoration ecologists are interested in using genetic characterizations to replace native habits with 'ecologically correct' populations. A measurement known as F-statistics is useful for examining population subdivision. F-statistics provide a measure of the nonrandom association of alleles within an individual and as such, describe the amount of inbreeding-like effects within subpopulations, among subpopulations, and within the entire population. Because most of our forage, turf, and native grasses are cross-pollinated, their high amount of within-population variation often obscures our ability to easily detect between-population differences. A technique known as analysis of molecular variance (AMOVA) is an easy to use, yet powerful, tool for examining population differences using molecular markers. AMOVA estimates and partitions the total molecular variance observed into components that are analogous to F-statistic parameters. Examples of AMOVA will be presented that address sample size, breeding history, and ecological adaptation of forage, turf, and native grass species. Finally, the use of discriminate analysis as a means to measure essential derivation will be demonstrated.