Utilization of the Randomly Amplified Polymorphic DNA (RAPD) technique as a molecular marker was tested to investigate the relationships between some representative grapevine cultivars and hybrids established at the Department of Genetics and Plant Breeding (CUB), to distinguish clones as well as to characterize various hybrids between spec...ies or cultivars and their parents. Vitis vinifera cultivars were easily and successfully distinguished by the RAPD technique and they were grouped according to the traditional taxonomic classification. RAPD patterns of the examined Pinot gris clones proved to be completely identical. Number of generations was reflected by the value of genetic distance of the examined hybrids. Genetic identity of parents and their offsprings was influenced by the selection applied in the process of plant breeding. Parental phenotypic and morphologic characteristics showed high degree of segregation in hybrids, but RAPD analysis revealed that their genetic similarity is considerable. The three Vitis anntrensis clones were properly discriminated from every cultivar and hybrid of Vitis vinifera, i.e. hybrids are much closer to the cultivated grapevine than to V. anzurensis due to the phenotypic selection carried out during the life-cycle of one or two generations.
The appearance of resistance to powdery mildew was investigated on seedling progenies of interspecific crossings. Hybrids of American and East-Asian wild species and one Vitis vinifera variety (Janjal kara) were used as source of resistance in the crossings. The resistance of foliage and of berries were tested in the field at the time ...of vintage. The degree of resistance was ranked into six classes.
In American and Asian hybrid derivatives there were few highly resistant progenies, but in the hybrids of Janjal kara variety more than 90 % of the progenies proved to be highly resistant to powdery mildew. According to the distribution of classes of resistance in the populations the resistance of American and Asian sources are mostly influenced by additive gene affects. The resistance of Janjal kara seemed to be mono or digenic.
No close correlation was found between the powdery mildew resistance of the foliage and that of the berries.