SEXUAL AND ASEXUAL REPRODUCTION IN NATURAL STANDS OF POPULUS-NIGRA

The balance between sexual and asexual propagation in the establishmen t of natural stands of Populus nigro was assessed from the genotypes o f trees sampled in different natural stands. One site was completely s ampled and genotyping proceeded using STS and RAPD markers. Among 118 trees, only four were vegetative copies of other trees of the site. Is ozymes were used in four stands, and a method to detect the presence o f vegetative copies in a sample is proposed for these markers. No vege tative copies were found in two cases, and a low number of copies was detected in the other two. Observations are reported for seedlings as well as for different modes of vegetative propagation in natural stand s. We conclude that sexual and asexual propagation play complementary roles in the dynamics of this species, and that in most cases the adul ts originate from seedlings.