Creation of high-quality varieties of common pear (Pyrus communis L.) in the Lower Volga region

Nowadays, the creation of high-quality pear varieties of different ripening behavior with early-, mid-, and late-season maturing is still relevant goal for breeders of the Lower Volga region. The long-term pome fruit breeding program, including pear breeding, is carried out in the Laboratory of breeding, seed production and nursery of the Federal Scientific Center for Agroecology, Land Reclamation and Protective Afforestation RAS. The parent forms involved in intervarietal and interspecific hybridization and targeted selection are mainly European varieties of high quality but low resistance to adverse climatic factors and local varieties of high resistance but poor fruit quality. As a result, new pears varieties were released, e.g., Dubovskaya rannyayya, Zimnyaya kubarevidnaya, Yubiley Korneeva, Nadazhda, Andreevskaya, Doktosxaya, Ordinata, Lavanda, Omega, Pamyat’ Korneeva, Kapella, Raketa, Positivnaya, Fermata, Banketnaya, Versiya, Nectarnaya, etc. Fully ripened fruits were collected in certain parts of the tree (early-ripening varieties) or at storage sites (late-ripening varieties) to determine quality parameters. Fruits were weighed on a laboratory scale and measured with a ruler to determine the average and maximum fruit weigh and size. Fruit appearance was assessed visually on a five-point scor, taste - by tastings carried out as the fruit ripened, on a five-point scor. The juice concentration of soluble solids was determined refractometrically. The total acidity was assessed by titration of an aqueous extract with 0.1 N alkali solution, sugar content (sum of sugars, mono-, disaccharides) was estimated by Bertrand’s method, pectin by carbazole method based on the interaction of carbazole with D-galacturonic acid, the vitamin C content by titration of oxalate extracts with Tillman’s reagent (2,6-dichlorophenolindophenol). It was established that the largest fruits (250 g and more) were formed by the varieties Pamyat’ Korneeva, Pozitivnaya, Kapella and Banketnaya. Since this trait is inherited from the parental large-fruited Olivier de Serre and Bakhmal cultivars, the new varieties, in addition to high commercial attractiveness, can be successfully used as sources in the creation of new large-fruited pear varieties of different ripening terms. The varieties Pamyat’ Korneeva, Nektar, and Fermata with excellent dessert balanced taste (4.7-5 points) and attractive fruit appearance surpass standard varieties in these traits. The genetic sources of the high taste quality of these varieties were the ancestral cultivars Alexandrine Dulyar and Bere Gardi with an exquisite taste and pleasant aroma. These genotypes can also be involved in future breeding for exquisite taste and commercial quality of fruits. The content of sugars in the fruits varied from 8.9 to 15.5 %, with the highest amount for the varieties Doktorskaya (15.48 %), Fermata (14.03 %), Versiya (16.3 %), and Kapella (15.5 %). These varieties also had the most balanced taste due to the low acid content. Biochemical composition, in addition to taste and quality, determines fruit suitability for processing and as an improver of finished (processed) products. For these purposes, the varieties Ordinate, Raketa, Kapella, Versiya, and Fermata and the most suitable. Therefore, of the released pear varieties, the varieties Pamyat’ Korneeva and Kapella outstand due to a complex of economically valuable features and are suitable not only for commercial production but also for further breeding program.