Seed set and germination in crosses within and between two geographically isolated small populations of Saxifraga hirculus in Denmark

Seed set and germination were studied in two geographically isolated populations of Saxifraga hirculus in Jutland, Denmark. The size of the populations differed, but both were assumed to exhibit significant genetic homogeneity and inbreeding due to (1) small population size (2) limited pollen flow and seed dispersal and (3) absence of gene flow between populations. Crosses within populations, as well as reciprocal crosses between populations, were carried out in the field. Seed number, proportion of developing seeds, germination percent, and germination rate were found to be greater for crosses between populations than for crosses within populations. Variation in seed size was found to be larger for maternal plants from the smaller population.