Relationship between Reaction Norm Variation and RAPD Diversity in Vicia dumetorum (Fabaceae)

Genotypes from 11 populations of the rare plant Vicia dumetorum (Fabaceae) were cloned and raised under two light regimes to assess the relationship between reaction norm variation and RAPD diversity. Analysis of variance revealed extensive plasticity and a significant main effect of clone and population for most characters, while consistent genotype x environment interactions were found only at the between-population level. The variance caused by differences between population means was usually lower than the variance attributable to differences between clone means within populations (34% vs. 66% when averaged over characters), while the genotype x environment interaction variance showed the opposite pattern (70% vs. 30%). The RAPD variation was low with an overall polymorphism of 5.3% and a Shannon diversity index of 0.008 (average over populations). Analysis of molecular variance revealed that the within- and between-population components accounted for 63% and 37% of the total variance, respectively. Clones from marginal and central populations differed little in reaction norm parameters and there was no significant association between interpopulation distances based on overall means across light regimes (reaction norm elevation), patterns and amounts of plasticity (reaction norm slope), and RAPD markers. Hence, comparisons of different suites of characters indicate some concordance between partitions of diversity (RAPD vs. genotype x environment interaction variance), while the geographic pattern in the three types of data appears to be different.