Evaluation of parental raspberry breeding forms for fruit size

Abstract

Te article tackles the feasibility of improving the raspberry fruit size as an important production and marketability factor. Te trials included 22 domestic and foreign cultivars, 11 selected forms of raspberry, as well as ten cross-breeding combinations and three open-pollinated forms. Te assessment of parental forms and hybrids was carried out at the collection and breeding sites of the Kokino base station of Federal Horticultural Center for Breeding, Agrotechnology and Nursery during 2016-2020. Fruits were harvested from regular cultivar bushes every 2 days in triplicate. Te average weight was determined per 100 berries in each replicate. Cultivars and hybrids were divided into three groups, small- (3.6 g). Te average berry weight in hybrid nurslings was estimated per plant. Each plant was sampled with 30 berries. Weighing was performed with an SCC-750 electronic scales device. Te weather conditions of the trial period were contrast, allowing a more objective assessment of the collection and breeding raspberry material by berry weight. Te following cultivars were identified as the sources of improved berry size in the parental form trials: Maria, Cascade Delight, Fenomen, Lavina, Cowichan, Patricia, Laczka, Glen Ample and selections 2-115-1, 8-13-2, 18-11-3, 18-11-2, 2-90-2 and 2-90-3. Tese forms had an average trial-period berry weight of 3.7-4.3 g least affected by weather conditions. Te inspection of hybrids revealed the best parental forms for obtaining new raspberry cultivars with an improved berry weight: Maria, Fenomen, Lavina, Cowichan, Glen Ample and the selected form 8-13-2. Te promising cross-combinations are: 2-12-1 x Fenomen, Lavina x Ulybka, 8-13-2 x Peresvet, as well as the open-pollinated offspring of Glen Ample, Cowichan and Maria. Large-fruited genotypes isolated in these lineages will be used in further breeding to increase the fruit size in raspberry.