Effect of growth regulators and substrate composition on the growth and development of garden strawberry (Fragaria × ananassa Duch.) at the acclimatization stage after in vitro cultivation

The ex vitro acclimatization of garden strawberry regenerants constitutes a critical stage in their in vitro propagation. The study was conducted in 2023–2024 using the facilities of the Biotechnology Laboratory of the Sakhalin Research Institute of Agriculture – Branch of the Federal Research Center All- Russian Institute of Plant Genetic Resources named after N. I. Vavilov. An optimal combination of various substrates and growth regulators for plant acclimatization to non-sterile conditions was identified. Ex vitro plants of the Nashe Podmoskovye garden strawberry responded to both the substrate composition and the applied growth regulators. A combination of the Krepysh and Terra Vita mixtures with all growth regulators produced a beneficial effect on the shoot biomass increment, improving biometric indicators by 10.3 % and 30.8 %, respectively, over the control. The application of the Kornyerost preparation to the plants grown in the Terra Vita and Krepysh substrates resulted in the growth of shoot biomass to 130.8 % and 123.3 % of the control, respectively. The Nasha Flora substrate, combined with the Etamon Bio preparation, provided a 66.7 % increase in shoot biomass, while with the Kornyerost regulator, the increase was 17.8 %. Treatment with Etamon Bio on the Terra Vita and Krepysh substrates increased this parameter by 5.1 % and 3.3 %, respectively, compared to the control. In the control variant, a soil mixture collected directly from the experimental field of the Institute was used as the substrate. The application of Geteroauksin and Kornyerost to this control substrate demonstrated an increase in shoot biomass by 113.3 % and 123.3 %, respectively, relative to the untreated control.