THE USE OF FLAVONOID GLYCOSIDES FOR THE IDENTIFICATION OF ELM HYBRIDS

The utilization of elm leaf flavonoids as biochemical markers for the identification of artificial and natural hybrids of elm species is dis cussed. Two to 11 individuals from controlled crosses of Ulmus carpini folia Gled., Ulmus pumila L., Ulmus parvifolia Jacq., and Ulmus japoni ca (R.) Sarg. were examined. Five to seven individuals from each paren tal species, and a number of putative hybrids between U. carpinifolia and U. pumila that naturally occur in central and northern Italy, were also examined. Quantitative data on leaf flavonoid glycosides were ob tained by means of high-performance thin layer chromatography and exam ined by multivariate discriminant analysis. The results show that it i s possible to identify the hybrid obtained between these species even if the parents are unknown, provided a number of individuals of the pa rental species are examined; therefore, it is also possible to certify putative hybrids. The higher variability of the flavonoid glycoside d ata of U. carpinifolia and U. pumila and the probable presence of F2 g eneration individuals make the certification of natural hybrids betwee n these two species in some cases difficult or even impossible.