Results of preliminary research on genetic variation and genetic differentiation between Wych elm populations (Ulmus glabra Huds.) in Poland

Wych elm (Ulmus glabra Huds.) is a rare scattered forest tree species in Poland. First studies on genetic diversity of the species in its natural range in Poland give a good basis for the management and conservation of its genetic resources. In the present study, we determined the level of genetic variation and genetic differentiation of seventeen natural Wych elm populations in Poland using nine nuclear microsatellite loci. The number of analyzed individuals was 601. The level of genetic diversity of Polish populations of Wych elm corresponded with the results of the previous studies on this species in Europe. The populations show quite low level of genetic diversity of the species on the population level and quite high diversity on the interpopulation level. A total of 119 alleles was found, with average number per locus (A) equal 6.0 and allelic richness at medium high level (AR10=4.7). Observed (Ho) and expected (He) heterozygosity reached 0.583 and 0.602 respectively. The genetic differentiation between Polish populations of Wych elm occurred at a low level (Fst=0.089). Inbreeding depression may occur in the next generations (Fis=0.031). Genetic diversity between Wych elm populations in Poland may be the result of unfavorable random processes related to the reduction of population size resulting from elm disease. To better understand the processes related to the genetic diversity of Wych elm populations, research on field elm variation should be undertaken. Such studies may give an answer to the potential influence of introgression between these species on the genetic structure of the Wych elm. Both in situ as well as ex situ conservation measures are highly recommended to preserve genetic resources of this valuable noble hardwood species in Polish landscape