Genetic Variation and Relationships of Japanese Populations of Oxalis corniculata L. (Oxalidaceae) Detected by Random Amplified Polymorphic DNA (RAPD)

RAPD analysis was applied to estimate the genetic variability in Japanese populations of Oxalis corniculata. This species comprises two floral morphs, homostyled and long‐styled, with different breeding systems (i.e., autogamy in the homostyled populations and mixed mating in the long‐styled populations). The number of RAPD phenotypes tended to be larger in homostyled populations than in long‐styled ones, and genetic diversity expressed by Simpson's indices of diversity was also generally larger in the former than in the latter. To examine the effects of breeding system on the levels of genetic differentiation among populations, two‐ and one‐level hierarchical variance partitionings were performed by the analysis of molecular variance (AMOVA). In two‐level AMOVA, significant variance component between the floral morphs was observed. In one‐level AMOVA, the proportions of variance partitioned among populations within each floral morph and among individuals within populations were similar in the homostyled and long‐styled populations, despite the difference in breeding system. To obtain insight into the relationships among individuals and/or populations, principal co‐ordinate analysis using 184 individuals (PCOA), and clustering analysis of 12 populations (UPGMA) were performed. PCOA indicated that the range of variation for homostyled individuals was more inclusive than that for long‐styled ones. A UPGMA dendrogram that consisted of two clusters showed that the long‐styled populations were nested in the homostyled ones.