Our objectives were to improve the rate of haploid plant regeneration throu
gh increasing the rate of callus initiation on the anthers and sustaining s
hoot regeneration frequency, and to analyze the field population of anther
culture origin by morphological and molecular methods. Regarding the callus
initiation, the most responsive clones were 'N-90' (59%) in P. nigra and '
D-29' (75%) in P. deltoides. The rate of shoot regeneration and number of s
hoots/calli ranged from 4%-79% and 1-9, respectively. From the 208 rooted p
lants 8 haploid, 179 diploid, 4 tetraploid and 17 aneuploid plants were fou
nd. In the field population, the haploid plants could be easily identified
by their retarded development and morphological characteristics (size and s
hape of the leaves, strong branching, etc). Several diploid plants showed d
epressed developmental and morphological traits similar to the haploid ones
. Three traits (growth rate, leaf blade length and shape of leaf base) of t
he 6 different morphological characteristics measured were in correlation w
ith the ploidy level within the poplar field population. Six primers of the
48 primers tested were able to detect polymorphism among the field plants.