Table 4. The association between the first three principal components extracted from principal component analysis of climatic variables and mean germination proportions of populations ofArabidopsis thaliana sampled in Fennoscandia and Italy examined with multiple regression. Germination proportion was recorded among seeds that had been stored dry for 1, 3 and 12 weeks after seed maturation in the greenhouse, and for 12 weeks after seed collection at an Italian and a Swedish field site. Statistically significant effects (P<0.05) are in bold.