Estimating the genetic relationship of hybrid bromegrass to smooth bromegrass and meadow bromegrass using RAPD markers

The two most widely grown bromegrass species in North America are smooth br omegrass, a hay type grass, and meadow bromegrass, a pasture type grass. Hy brid populations between these two species have been developed through hybr idization and recurrent selection. The objective of this study was to deter mine the genetic relatedness of the hybrid bromegrass population S-9073M to its parental populations using random amplified polymorphic DNA (RAPD) mar kers and to determine genetic variation within and between populations. Ind ividuals from each of the three populations were genotyped at 43 polymorphi c RAPD loci. One of the RAPD fragments was meadow bromegrass-specific. Clus ter analysis showed three groups representing the two parental populations and the hybrid population. An analysis of molecular variance (AMOVA), showe d that the hybrid population had the highest within-population variation, f ollowed by meadow bromegrass and smooth bromegrass. The interpopulation gen etic distance (phi-statistic = Phi (st)) was highest between meadow and smo oth bromegrass and lowest between smooth and hybrid bromegrass. The hybrid population was genetically intermediate to smooth bromegrass and meadow bro megrass, but closer to smooth bromegrass, possibly reflecting the selection criteria used in the development of this hybrid.