Evaluation of raspberry cultivar samples by productivity components

The study has been carried out to evaluate raspberry cultivar samples by productivity, its stability over the years of the research and to identify the components that make the greatest contribution to increasing yields in the conditions of the Bryansk region. The study was conducted in 2022–2024. The objects of the research were 21 raspberry cultivar samples planted in 2020. The biological productivity accounting of cultivar samples and its components, statistical processing of data was carried out using generally accepted methods. The results of the analysis of variance for the period of the research by the productivity components of cultivars and selected forms indicate the presence of reliable differences in the influence of cultivar, year, as well as their interaction. No cultivar samples have been identified as sources of a complex of high-level productivity elements that are consistently evident over the years of the research. The highest number of fruit-bearing stems per bush (5.6 pieces) was formed by selected form No. 8-6-3 (Russia) with genotypic control of the index (70.0 %). The long laterals (more than 20 cm) were noted in cultivars ‘Balzam’, ‘Skromnitsa’ and selection 6-125-4 (Russia) with a high degree of trait control by genotype (41.9–56.7 %). The sources of increased number of laterals on the stem (21.6-27.0 pieces) were cultivars ‘Lavina’, ‘Gusar’, ‘Balzam’ and selection 8-6-3 (Russia) with the influence of genotype on the manifestation of the index from 52.6 to 85.5 %. The highest number of berries per lateral (14.4 pieces) with the lowest variability by years (25.0 %) is formed by selected form 2-90-3 (Russia). The introduced cultivars ‘Glen Magna’, ‘Glen Ample’ (Great Britain), ‘Sokolica’ (Poland), as well as the genotypes of Russian breeding ‘Lavina’ and 6-125-3 with genetic control of the indicator at the level of 65.3–93.8 % were distinguished by large-fruitfulness (3.6–4.3 g) and stable manifestation of the trait over the years of the research (6.3–31.0 %). Correlation analysis allowed to establish that the contribution of productivity components to the total yield is different and varies depending on environmental conditions, so the selection of highly productive plants in raspberry progeny should be carried out for all components and breeding process to increase the level of each of them.