Clonal micropropagation of day-neutral varieties of garden strawberry (Fragaria x ananassa Duch.)

Abstract. The article presents the results of the evaluation of the efficiency of clonal propagation of commercially promising day-neutral varieties of garden strawberry. Day-neutral strawberry varieties usually form fewer rosettes on a plant during the growing season than regular varieties, and therefore vegetative propagation is ineffective for these varieties. The aim of the study is to increase the efficiency of propagation of day-neutral varieties of garden strawberry (Fragaria x ananassa Duch.), characterized by weak runnerforming ability, by optimizing the process of microclonal propagation in vitro and subsequent adaptation of regenerated plants to ex vitro conditions. The article indicates the features of microclonal propagation technology of neutral-day strawberry varieties Vivara, Sweet Eve and Evis Delight. The studies were conducted in the laboratory of the Federal State Budget Scientific Institution NCFSСHVW in 2022-2023. MurashigeSkoog (MS) agar medium with the addition of plant growth regulator 6-BAP was used as the main medium (at the introduction stage – 6-BAP – 0.2 mg/l, at the micropropagation stage – 0.75 mg/l, hormone-free MS medium – control). As a result of the studies, it was found that the variety of garden strawberry Sweet Eve is characterized by a higher shoot-forming ability. At a 6-BAP concentration of 0.75 mg/l in the medium, an average of 10.5 new shoots are formed from one shoot in the third passage. Evis Delight variety showed a low shoot-forming capacity of up to 3.8 shoots/exp. After the fourth passage, even on a hormone-free medium, Sweet Eve variety showed an aftereffect of 6-BAP, with the formation of an average of 8.8 shoots from one explant. Such a strong aftereffect of 6-BAP was not noted in Vivara and Eve’s Delight varieties. Rooting began after the fifth passage on a hormone-free medium. The root formation efficiency was 95- 100%. At this stage, longer shoots up to 5.9 cm and roots up to 4.8 cm are formed in Vivara variety. Evis Delight variety stood out in terms of the number of leaves (an average of 9.1 pcs.) and roots (7.5 pcs.). The use of the biopreparation Agrinos 1 at the adaptation stage had a positive effect on the formation of the vegetative mass and root system of strawberry plants. The application of the preparation at a concentration of 5 ml/l promotes the growth of the root system, the length of which is 1.6-2.2 times greater than the length of the roots in the control variant. The number of leaves increases by 1.1-1.3 times, and the average height of the bushes is 1.5-1.7 times greater than the control values. Key words: clonal micropropagation, day-neutral strawberry, 6-benzylaminopurine, multiplication factor, microshoots