VARIATION AND RELATIONSHIP OF TRAITS OF UNGRAFTED AND GRAFTED HYBRIDS OF DIFFERENT PRUNUS CERASUS X PRUNUS CANESCENS COMBINATIONS

In the Giessen programme for breeding dwarfing rootstocks for sweet cherries, Prunus cerasus x P. canescens hybrids proved very successful. Therefore, comprehensive analyses of data of this material were initiated to support further selection within seedlings from this cross combination. Variation of all features studied (various vegetative and generative traits) was high for the ungrafted hybrids. No influence of the crossing direction was found and an effect of the parental cerasus-cultivar (‘Schattenmorelle’ or ‘Leitzkauer’) occured for only for two characteristics. Correlation between traits of ungrafted and grafted plants were not very strong. No possibility for preselection on yield potential was discovered. However, results may support the selection of candidates which induce less vigour than Gisela 5: ungrafted hybrids with low weight, slender stems, moderate new growth and late blooming period seem to be more promising than others. A rootstock trial of candidates is planned.