DIFFERENTIATION OF WALNUT HYBRIDS (JUGLANS NIGRA L. x JUGLANS REGIA L.) THROUGH RAPD MARKERS
Randomly Amplified Polymorphic DNAs (RAPDs) were used to discriminate 16 F1 hybrids (Juglans nigra L. x Juglans regia L.), provenance Orleans, 11 F1 hybrids (J. nigra x J. regia), provenance Bordeaux, 4 back crosses [(J. nigra x J. regia) x J. regia], 4 back crosses [(J. nigra x J. regia) x J. nigra]. The species J. nigra was represented by one genotype, NG23, whereas the possible pollinators were four J. regia individuals: RA 984, RA 996, RA 311, RA 295. All crosses and back crosses were obtained from free pollination. A set of 80 random sequence 10-mer primers were tested. Twenty of them showed strong and polymorphic bands. A matrix based on presence (1) and absence (0) of bands was performed. Different algorithms were used to assess the genetic similarity among the plants tested by means of NTSYS statistical package. The UPGMA cluster analysis revealed a weak differentiation among the F1 hybrids of both provenances. A high similarity was observed among the 4 J. regia individuals. On the other hand, they were well differentiated from the J. nigra NG 23 genotype. The 4 back crosses [(J. nigra x J. regia) x J. nigra] resulted clustered to the J. nigra NG23, whereas the 4 back crosses [(J. nigra x J. regia) x J. regia] were divided from the J. regia plants tested. On the basis of the obtained results, some hypothesis about the genetic origin of the tested hybrids and back crosses have been proposed.
Emilia, M., Spada, M., Beritognolo, I. and Cannata, F. (1997). DIFFERENTIATION OF WALNUT HYBRIDS (JUGLANS NIGRA L. x JUGLANS REGIA L.) THROUGH RAPD MARKERS. Acta Hortic. 442, 43-52