Abstract
In order to clarify the relationships among 23 cultivars or strains of 5 species, L. perenne, L. multiflorum, L. rigidum, L. remotum, and L. temulentum, in the genus Lolium, leaf materials sampled from 483 plants were assayed by the horizontal starch gel electrophoresis for an enzyme system, phospho-gluco isomerase (Pgi-2). The results obtained were as follows: 1. Seven bands were detected on the zymograms of Pgi-2, and the existence of 10 zymograms in all was confirmed. 2. Pgi-2 isozyme pattern was independent of the leaf age. 3. For the inbred species, L. remotum and L. temulentum, all plants of each species examined were identical with a common simple banding pattern. For the outbred species, L. perenne, L. multiflorum, and L. rigidum, several different zymograms were observed in each cultivar or strain. 4. Since all of the outbred species could not be identified with a common simple banding pattern, Nei's genetic distance for testing the distinctiveness and the relationships of cultivars, strains and species in the genus Lolium, was applied. As the results, it was suggested that L. rigidum was most similar to L. multiflorum, L. perenne was comparatively similar to L. rigidum, L. multiflorum, L. remotum and L. temulentum, and both L. rigidum and L. multiflorum were most different from both L. remotum and L. temulentum. Besides, it was assumed that L. remotum was exceedingly similar to L. temulentum. 5. Assumption on the phylogenetic relationships among Lolium species obtained from the above mentioned results coincided nearly with the Terrell's hypothesis (1968). Further-more, the grouping of L. multiflorum cultivars (2n=14) on the basis of Pgi-2 isozyme coincided well with the grouping of those cultivars on the basis of peroxidase isozyme variation in the author's previous paper (1982).
