Evaluation of remontant type raspberries original forms and progeny by soluble dry substances content in fruits

The objective of research is to evaluate the source material of remontant raspberries for the content of soluble dry substances (SDS) in fruits in the conditions of the Non-Black Earth Region of Russia, to identify the possibility of increasing this indicator through selection and to identify promising crossbreeding combinations. The study was conducted in 2021-2023 on experimental plots of the Kokino Base Station (Bryansk Region). The objects of research are fruits of 28 remontant raspberry varieties, as well as 466 hybrid seedlings of 7 crossbreeding combinations. The studies were carried out in accordance with generally accepted methods. On average, the level of SDM accumulation for all varieties was almost the same annually and amounted to 9.3 °Brix. The range of variation of the studied indicator was from 6.9 °Brix for the Nizhegorodets variety (2021) to 11.7 °Brix for the Brice variety and the selected form 1-16-11 (2023). On average, over the years of research, the varieties Atlant, Poklon Kazakovu, Karamel'ka and Bab'e Leto were among the best in terms of accumulation of SDS in fruits (10.2-10.4 °Brix). The hybrid offspring of the cross combinations were mainly represented by seedlings with a low ( 12.0 °Brix) was even lower - 1.7-6.9 %, and such genotypes were not found in all families. The best transgressive seedlings accumulated an average of 12.1-12.3 % of SDS. In the family Podarok Kashinu × 1-16-11, 2 genotypes with the maximum content of SDS (13.2 and 14.0 %) were isolated. The selection of transgressive seedlings indicates the possibility of increasing the level of SDS by selection.