Introduced by E.P. Finaev at the Kuybyshev Experimental Garden Station for fruit growing through crossing of the 'Ternosliwa Kuybyshevskaya' and 'Renklod Bavay' varieties. Registered in the State Register in 1988 for the Middle Volga region.
Medium-sized, fast-growing tree. Crown is oval-spherical, medium density. Fruit-bearing on 2-3-year-old branches. Bark on the trunk and main branches is smooth, gray-green. Shoots are thick, straight, red-brown, bare. Buds are few, medium-sized, white. Leaves are medium in length and width, egg-shaped, short-pointed, dark green, wrinkled, matte. Leaf blade is flat, leaf apex is short-pointed, base is rounded, no pubescence. Leaf margin is doubly toothed. Petioles are medium in size and thickness. Stipules are small, 1-2, yellow, rounded. Inflorescence — solitary flowers, medium, white.
Fruits are medium, one-dimensional, average weight 25.1 g. Shape is oval-round, apex rounded, base with indentation, pit small. Ventral suture is small, barely noticeable. Pedicel is medium in length and thickness, easy detachment from branch, weak attachment to stone. Main color is green, covering color is blue, solid. Subcutaneous dots: medium number, white. Skin is medium, bare, with strong waxy coating, difficult to remove. Flesh is green, tender, juicy, cavity color is uniform with flesh. Juice is colorless. Taste is sour-sweet. Stone separates moderately from flesh, medium, egg-shaped, blunt, in pits. Fruits contain dry matter — 14.3%, sugars — 9.25%, acids — 1.47%, ascorbic acid — 5.86 mg/100g. Main use is universal. Fruits are suitable for making jams and compotes.
Flowering from May 10-20. Fruit ripening period is medium-late. Harvesting period is August 12-22. Fruit quality is good. Transportability is good. Fruits harvested 3-5 days before ripening can be stored for 10-12 days. Trees enter fruiting stage at 5-6 years. Yield of 'Kuybyshevsky Blue' is quite high: at 7-8 years — up to 25-30 kg, at 9-12 years — up to 25-30 kg. Healthiest trees yield up to 45 kg per tree. Annual fruiting. Fruits remain well attached on the tree, do not drop.
The variety is fairly self-fertile. Best pollinators for this variety: 'Red Early', 'Zhiguli', 'Mirnaya', 'Ternosliwa Kuybyshevskaya'.
Winter hardiness of trees is fairly high. During the winter of 1978/79, trees had an overall degree of freezing damage of 1.2 points. Drought resistance is medium. Not susceptible to moniliosis. Susceptibility to gummosis is low. In some years, fruits are affected by plum fruit moth at 0.5%.
Propagated by grafting onto seedling rootstocks of 'Red Early', 'Ternosliwa Kuybyshevskaya', 'October Hungarian'. Grows best on elevated areas and gentle slopes. Requires well-drained soils of light and medium texture — sandy, loamy, and light clays. Young trees require formative pruning, older trees require rejuvenating pruning.
Advantages of the variety: high annual yield.
Disadvantages of the variety: fruits are not large enough.
