Genetic variation of the riparian pioneer tree species Populus nigra L .1. Study of population structure based on isozymes

Eight polymorphic isozyme loci were used to describe the level and organization of the genetic diversity in Populus nigra L. over 111 sites in France and among 60 additional individuals from throughout the species range. Best descriptors and estimators of gene diversity and differentiation were sought. Overall diversity level was found to be comparable to other widespread species. Differentiation at three geographical scales was low, although local allele fixations indicated limitation of gene flow. Inferences were made on the effect of the natural history of the species on the organization of neutral diversity, and recommendations for collection of genetic resources were derived.