Purpose. To evaluate hazelnut cultivars, species and hybrids from the genetic collection of Corylus spp. in the National Dendrological Park “Sofiyivka” of the NAS of Ukraine for the complex of economic characters. An attempt has been made to analyze the information on Corylus spp. identity, taxonomy and description, dissemination and ecological requirements of the species, possibilities to use the genetic potential for developing new cultivars. Methods. The value of the Corylus spp. collection representatives was investigated using conventional testing procedures. For summarizing information concerning phylogenetic reconstruction of the Corylus L. genus and hazelnut, a number of scientific publications to be proposed for discussion was analyzed. The oil content in hazelnut kernels and the fatty acid composition was determined using official methods. Results. The best samples of hazelnut genetic collection were included into the broad hybridization programme, and C. chinensis Franch. representatives as well. A number of hybrid seedlings was obtained including new hazelnut cultivars ‘Sofiyivsky 1’, ‘Sofiyivsky 2’ and ‘Sofiyivsky 15’ which were characterized by spherical or almost spherical fruits, high winter hardiness and drought resistance, as well as the absence of rhythmicity in fruiting. Conclusions. The collection of varieties, forms, cultivars and species of the Corylus L. genus created during the last years can be the base for hazelnut breeding in Ukraine.

Purpose. Determination of optimum dozes of foliar fee­ding for each cultivar that will provide the highest output of standard rootstocks. Methods. Field, analytical and statistical ones. Results. The author presents the results of study of the hazelnut plant foliar feeding in the mother plantation for vegetative propagation with applying different carba­mide concentration combined with 0.1% potassium sulfate (1.50.4 m) in case of horizontal method of growing. Biometric indices of hazelnut layers were analyzed; the influence of each factor on their height and diameter was determined. The rootstocks output per 1 linear meter for each cultivar as well as optimum foliar feeding doze was defined (0.5% carbamide with 0.1% potassium sulfate). Conclusions. The highest output of standard rootstocks in the mother plantation for horizontal vegetative propagation was achieved when applying the foliar feeding with 0.5% carbamide combined with 0.1% potassium sulfate, particularly (thousand rootstocks per 1 ha) for the cultivars: ‘Sviatkovyi’ – 66.7, ‘Dolynskyi’ – 62.1 and ‘Darunok Yunnatam’ – 50.7. For ‘Koronchatyi’ cultivar, the use of 3% carbamide was the most efficient.