Genetic variation within and between populations of the asexual plant Puccinellia x phryganodes

Puccinellia x phryganodes (Trin.) Scriber and Merr is widely distributed in Arctic salt marshes. In North America the species, which is capable of extensive clonal growth, appears to be a sterile triploid (2n = 21) ; seed set has never been observed. Consequently it was predicted that the level of genetic variation would be low, both within and between populations. Examination of electrophoretic mobilities of isozymes of 12 enzyme systems in plants from three widely separated populations in Arctic Canada indicated a high level of variability both within and between the populations. The unexpected discovery of significant amounts of genetic variability suggests that sexual processes occur in this species.