Plant variety assessment of garden strawberry based on fruit strength

Abstract

This article investigates the possibility of obtaining genotypes of garden strawberry with enhanced fruit strength. The creation of species and varieties with the specified feature is expected to improve the quality, transportability and storability of berries. Experiments were performed in 2015–2020 at the collection and breeding plots of the Kokinsky testing station of the Federal Horticultural Research Centre for Breeding, Agrotechnology and Nursery. 29 species of the domestic and foreign selection, 7 choice species, as well as the hybrid seedlings of 22 crossing combinations and 3 open pollination populations of garden strawberries, were investigated. The aim was to identify sources of increased trength and perspective crossing combinations, affording the highest yield of seedlings with firm fruits. The examination of the fruit strength was performed at the stage of optimal maturity. Berries crushing force was determined using a VR-04MS-2-BR balance by applying pressure to the fruits until the first drop of juice appears. The measurement results were converted into international units, i.e., Newtons (1 kg = 9.8 N). The phenotypic evaluation of varieties and species of garden strawberries based on the fruit strength revealed genotypes with the firmest fruits — Kleri, Darselect, Tenira, Selekta, Polka, Tzaritza, Aquarelle, Irma and the 3-366-9 selection. These varieties yield the fruits, which endure the crashing force of over 10 N. In the hybrid progeny, the fruit strength varied within a wide range, and its significant change within the crossing combinations and populations of open pollination was revealed. The Darselect, Cleri, Irma, Tzaritza varieties are the most valuable seed parents in the transmission of the high strength character. Within the research period, the best crossing combination yielding seedlings with fi m fruits were Alfa×Darselect, Festival Romashka×Darselect, Irma×Lyubava, 3-366-9×Kleri, Nashe Podmoskovye×Irma, Festival Romashka×Kleri and open pollination population of the Kleri, Darselect, Tzariza varieties. 42.2 to 60.3 % of hybrid seedlings yielded fruits with the crushing force of over 10 N, and an average value for the families amounted to 9.6–11.2 N.