Phosphoglucoisomerase-2 allozymes for distinguishing perennial ryegrass cultivars in binary mixtures

Abstract

SummaryThe analysis of Kennedyet al.(1985) was applied to 150 individuals from each of six plots containing mixtures of the perennial ryegrass (Lolium perenneL.) cultivar Grasslands Nui and the resident ryegrass population at Rawhiti, Central Wairarapa, New Zealand. Four alleles (A, B, CandD) were identified at the phosphoglucoisomerase-2 allozyme locus in the two ryegrass populations. Using the maximum likelihood method, non-linear models were fitted to calculate the percentage contribution of Grasslands Nui to the mixtures. The contribution of Grasslands Nui to the six evaluation plots ranged from 5 to 44%, with S.E.S of 11–17%. The lowest contribution occurred under set stocking with sheep and a low fertilizer regime. The persistence of Grasslands Nui under contrasting grazing managements and fertilizer regimes in this dry environment, and aspects of enzyme electrophoresis application to field trials, are discussed.