VARIATION IN CONE MORPHOLOGY AND SEED CHARACTERS IN PINUS-STROBUS IN QUEBEC

To investigate the patterns of variation in white pine (Pinus strobus L.), 10 natural populations from Quebec were compared using the phenot ypic variation of cone and seed traits. Eight characters were measured on 10 cones collected from 30 trees in each of the 10 sampled populat ions. Four populations were from the Ottawa River region and four from the St. Lawrence Lowlands region, while two populations were at the m argin of the natural range of the species in Quebec, from the Abitibi region and Anticosti Island. Significant differences among populations were detected for each character. Estimates of repeatability of these traits were relatively high, suggesting substantial genotypic control over them. These estimates were consistent from population to populat ion. Results of multivariate analyses suggest that populations from th e Ottawa River region are similar to those from the St. Lawrence regio n, with populations from these regions diverging only in cone scale le ngth. However, populations from the St. Lawrence region were more dist inct from each other than those from the Ottawa River region. The popu lation from Abitibi deviates considerably from the other populations, suggesting habitat-selection pressures acting at the margin of the nat ural range of the species under continental conditions. Finally, no ge neral geographical trend was detected in the observed variation.