The article describes results of a comparative study of variability of 14 quantitative characteristics of biochemical composition of fruits in sort rows of 4 species of introduced varieties of Ericaceae (Oxycoccus macrocarpus, Vaccinium corymbosum) and Actinidiaceae (Actinidia arguta, Actinidia kolomikta) families, which has shown its lowest dependence on genotype in O. macrocarpus and the greatest dependence in A. arguta while the species studied have similarities in the level of genetic determinancy of a number of characteristics of fruits biochemical composition. It has been shown that the lowest stability in sort rows of both species of Ericaceae fam. is typical of parameters of accumulating anthocyanins proper and leucoanthocyanins while the greatest stability – that of ascorbic acid, which is characterized by high variability in both species of Actinidiaceae family. Most species of introduced plants studied have the lowest variability in sort rows in content of soluble sugars and total amount of bioflavonoids in fruits, while the greatest one – in sugar-acid index and tannins content. It has been found out that V. corymbosum and A. arguta have little dependence of flavonols content in fruits on genotype while V. corymbosum and A. kolomikta – that of pectin substances with a strong dependence of parameters of accumulating the latter in O. macrocarpus and A. arguta.

The State Register of Plant Varieties of the Republic of Belarus includes 6 varieties of large-fruited cranberry: Ben Lear, Franklin, Howes, McFarlin, Piligrim, Stevens. Based on the results of the study, it was determined that the morphological features of the leaf, stem and fruit of the large-fruited cranberry are plant-specific indicators and make it possible to identify the taxa of this crop.

The article indicates morphological features of vegetative and generative buds of 20 varieties of highbush and 3 varieties of halfhighbush blueberry. Generative buds are laid in the upper part of branching shoots, less often on replacement shoots. Flower buds are much larger than vegetative buds, ovoid, from 3.9 (Jersey) to 6.5 mm (Hardyblue) long, from 2.0 (Herbert, Patriot) to 2.7 mm in diameter (Reka). Depending on the varietal specificity, on average, from 1.3 (Carolinablue) to 6.3 (Rubel) generative buds are formed on one shoot of highbush blueberry branching. The peak number of fruit buds can reach 11 pcs/shoot (Rubel). Vegetative buds are cone-shaped, from 1.8 (Bluecrop, Darrow, Herbert) to 2.8 mm (Jersey) long, from 1.1 (Blueray, Darrow, Jersey, Northblue, Rubel, Weymouth) up to 1.5 mm (Bluetta, Coville) wide. Depending on the variety, on average, from 4.8 (Nelson) to 8.4 (Weymouth) growth buds are laid on the branching shoot. The ratio of vegetative to generative buds on one run varies on average from 1.0 (Rubel) to 6.7 (Bluetta). The linear parameters of the kidneys increase from the base of the shoot to its top.

The article describes results of a comparative study conducted in seasons of contrasting hydrothermic regimes of averaged variation coefficients of 14 indexes of biochemical composition of fruits of 4 species of introduced plants from families Ericaceae and Actinidiaceae – O. macrocarpus, V. corymbosum, A. arguta and A. kolomikta. It has been shown that the highest integral resistance of biochemical composition of fruits to the complex impact of meteorological factors among O. macrocarpus varieties is characteristic of the released Stevens variety, the lowest one – of Holistar Red, among V. corymbosum varieties – of Bluejay and Sunrise respectively. In the taxonomic row of A. arguta the highest resistance to abiotic factors is found in the natural form, the lowest one – in Sentjabrskaja variety, in the taxonomic row of A. kolomikta – in Aromatnaja and Sentjabrskaja varieties respectively. The greatest variability in all or most introduced varieties is characteristic of parameters of accumulation in fruits of dry substances, hydroxycinnamic acids, soluble sugars and the total amount of bioflavonoids, as well as the content of pectin substances for both species of Actinidiaceae family. At the same time, O. macrocarpus is characterized by high stability of the content of titrated acids and anthocyanin pigments in fruits, V. corymbosum – of catechins, flavonols and tannins, A. kolomikta – of titrated acids, leucoanthocyanins and catechins. Accordingly, the most distinct dependence on the seasonal hydrothermal regime has been found in O. macrocarpus for its sugar-acid index and the content of catechins in fruits, in V. corymbosum – for that of pectin substances and true anthocyanins, in A. arguta – for catechins content, for A. kolomikta – for that of ascorbic acid and flavonols.