Electrophoretic variation as a measure of speciesdifferentiation between four species of the genus Lolium

Isozyme electrophoresis was carried out on 423 accessionsbelonging to four species of the genus Lolium toassess the genetic variation within and between the species. Fourenzyme systems (acid phosphatase, glutamate oxaloacetatetransaminase, phospho-gluco isomerase and superoxidedismutase) were used to array allelic diversity at fivepolymorphic loci. Nei's genetic distance analysis andmultivariate analyses were computed and the taxonomic position ofeach species is discussed as a result of these computations.Electrophoresis is shown to clearly differentiate the inbreedingspecies, L. temulentum fromthe outcrossing species, L.perenne, L.multiflorum and L.rigidum, and to separate the species within theout-breeding group. The taxonomic results are discussed inrelation to an earlier paper on morphological variation, concludingthat electrophoresis is a valid taxonomic tool showing distinctseparations between the species, but that current plant breeding andagricultural practises may be increasing the amount of hybridisationbetween the species than occurred in the past.