FINE FESCUE SPECIES DETERMINATION BY LASER FLOW-CYTOMETRY

The close morphological resemblance among fine fescues (Festuca spp.) makes identification and classification of species a difficult problem for turfgrass and taxonomic scientists. Determining ploidy level has become a major taxonomic tool for identifying species of fine fescues. The present study used laser flow cytometry to determine ploidy level s of 48 fine fescue populations (accessions) and thereby infer species classification based on observed and previously reported chromosome n umbers. The 10 species of fine fescues examined were strong creeping r ed fescue (F. rubra L. spp. rubra), slender creeping red fescue (F. ru bra ver, littoralis Vasey), Chewings fescue [F. rubra ssp. fallax (Thu ill.) Nyman], hard fescue (F. brevipila Tracey), sheep fescue [F. ovin a L. ssp. hirtula (Hackel ex Travis) Wilkinson], hair fescue (F. filif ormis Pourret), false sheep fescue (F. pseudovina Hackel ex Wiesb), al pine fescue (F. brachyphylla Schultes), bluebunch fescue (F. idahoensi s Ebner), and tundra fescue (F. lenensis Drobov). Significant differen ces were observed between species (P < 0.01) and among populations wit hin species (P < 0.05). DNA content among the 10 species was observed to be highly positively correlated with observed or reported chromosom e numbers (r = 0.97, n = 10, P < 0.01). Linear regression analysis (Y = 2.1 + 0.23 X) predicted 2C DNA content values for each of the four p loidy levels to be 5.31 pg for diploids (2n = 2x = 14), 8.53 pg for te traploids (2n = 4x = 28), 11.75 pg for hexaploids (2n = 6x = 42), and 14.98 pg for octoploids (2n = 8x = 56). The observations and results o f the present study are consistent,vith current taxonomic treatments o f hard and sheep fescue species as web as the other fine fescue specie s examined. The information presented should aid breeders in accuratel y and easily determining primary breeding germplasm with respect to pl oidy levels. It may also enable the turfgrass industry to define relia bly seed products and the plant collector to begin to assign native an d/or naturalized accessions to their proper species categories.