Identification of hybrids between Quercus petraea and Q-robur (Fagaceae):: results obtained with RAPD markers confirm allozyme studies based on the Got-2 locus

RAPDs were employed as genetic markers to detect interspecific hybridization between the closely related oak species Quercus robur and Q. petraea. Fourteen primers were used in order to check the genetic status ("pure" or hybrid) of individuals classified morphologically. Among the 147 PCR fragments obtained 11 appear to be species-specific. In the phenotypically intermediate individuals different combinations of these species-specific bands were obtained. The patterns in these putative hybrids were not additive, which may be either the result of repeated backcrossing and introgression between the two species or of heterozygosity within the parental species. The results of the RAPD study are consistent with morphological analyses and allozyme data obtained for the Got-2 locus. Thus the RAPD markers used in this study may provide a powerful genetic tool for the identification of hybrids and the discrimination between the two "pure" species.