CONSERVATION OF ALLELIC MULTIPLICITY AND GENOTYPIC FREQUENCY BY POOLING WILD POPULATIONS OF PERENNIAL RYEGRASS

Three experimental breeding populations, created by pooling four to five natural populations of perennial ryegrass, were used to indicate the effect of sampling and pooling on the retention of genetic variation. Conservation of allelic multiplicity and genotypic frequencies was observed using allelic frequencies measured on six isozyme markers. We observed that by bulking four or five natural populations, represented respectively by 25 or 20 plants, in a large polycross design, the allelic and genotypic frequencies of the original mother-plants were conserved. There was no loss of rare alleles (0.01 < p < 0.10) in the three experimental populations compared with the original natural populations. Only very rare alleles (p < 0.01) were reduced in frequency or lost. The value of such a bulking approach is discussed and presented as a possible alternative to the core collection approach to the management and use of genetic resources of perennial ryegrass.