Genetic variation in cultivars of diploid ryegrass,Lolium perenne andL. multiflorum, at five enzyme systems.

Samples of approximately 100 plants from each of 22 populations ofLolium perenne representing 15 cultivars, and from 13 populations ofLolium multiflorum representing six cultivars were scored for iso-zyme variants in five enzyme systems, PGI, GOT, ACP, PGM and 6-PGD. From the individual banding patterns a genetic interpretation of the variation was formulated and population studies of the resulting six polymorphic enzyme loci were performed. No strong indications of partial selfing was found since at four of the six loci,Pgi 2, Got 3, Pgm 1 andPgd 1, the genotypic proportions were in correspondence with the Hardy-Weinberg expectations. This indicated, further, that the genetical interpretations of the banding patterns might be correct. Deviations from Hardy-Weinberg proportions forAcp 1 andGot 2 indicated presumably selection working on the linkage group including these loci. Gametic phase disequilibrium was observed betweenPgi 2 andPgd 1 for populations of one cultivar. These results were discussed in relation to the variation expected within a cultivar.