The hazelnut (Corylus domestica Kos. et Opal.) breeding program in National dendrological park "Sofiyivka" of NAS of Ukraine
Authors: Kosenko I. S. , Opalko A. I. , Balabak O. A. , Opalko O. A. 
Published: July 2020

Aim. The necessity to develop new domestic hazelnut cultivars with the nuts of a globular shape and well-adapted to local conditions, and serious lagging behind of local hazelnuts production which has both to satisfy nut consumption needs and to provide processing industry, and first of all its confectionary branch, with raw material, and also to create the foundation for entering foreign markets, motivated the search for the accelerated breeding methods of this valuable plant. Methods. The research was carried out in the years of 2012–2016 on a hazelnut nursery which belongs to the department of genetics, breeding and reproductive plant biology of the National dendrological park “Sofiyivka” of Ukraine’s NAS. A crossing scheme included several local and introduced cultivars and representatives of C. chinensis Franch., which were used due to their being a source of large nut its, high content of raw protein and oil and large output of kernels in the nuts. The production technology of hazelnut in the trial was standard for the Forest Steppe zone of Ukraine. Results. A new breeding scheme, which included the elements of accelerated breeding in addition to traditional stages of choosing pairs for hybridization, crossing and evaluation of the seedlings of the first F1 generation, comprehensive evaluation of chosen seedlings in the orchard of preliminary cultivar studying, preparation of the best of them for the expertise with the aim of further submission to the State registry of the cultivars suitable for cultivation in Ukraine, was worked out. In particular, it is the accelerated passing of breeding material through the stages for 3–4 years, which is possible at the stage of growing seedlings of the first F1 generation in a hybrid orchard (1–2 years) and accelerated layering propagation of the best seedlings (1–2 years). Due to the fact that a wide spectrum of splitting as to numerous economic-valuable indicators was observed both in seed progeny and from controlled crossings and from free pollination, promising forms from 44 seedling populations were chosen for successive hybridization cycles and cultivar studying aimed at further use in polyclonal plantations where interclonal pollination would be possible. This made it possible to receive valuable hybrid seedlings with globular fruits, one of them started fruiting in the third year after crossing; now it is propagated as cultivar Sofiyivskyi 15. Although in the first year this seedling developed only female flowers, it did not prevent from doing organoleptic evaluation of fruits, resulted from crossed free pollination. Conclusions. The efficiency of a hazelnut breeding scheme, worked out by us and which included the best cultivars of the collection of NDP “Sofiyivka” in controlled crossings and the representatives of Chinese hazelnut C. chinensis, that were used because of their large fruits and high content of raw protein and oil, and the accelerated passing of the selection material through the stages of the scheme for 3–5 years, was confirmed by the development of valuable breeding material, and candidates to become cultivars were chosen from it, namely 'Sofiyivsky 15' which started fruiting on the third year after crossing and was characterized by adaptability and a globular shape of fruits.

Keywords: Corylus spp., cultivar Sophiyivsky 15, hazelnut hybrids, nut crops, sporophytic self-incompatibility, S-allele of the self-incompatibility genes.