Growth and development of regenerant strawberry (Fragaria × ananassa (Weston) Duchesne ex Rozier) plants on various vermiculite substrates during transfer from in vitro to ex vitro conditions

The composition of substrates plays an important role in the adaptation of regenerated plants during their further cultivation in natural conditions. The article presents the results of an experiment on the use of thermovermiculite of the Kovdor deposit of the Vipon-2 and TV2-N brands, differing in the production method, for the adaptation of regenerated pineapple strawberry plants (Fragaria × ananassa) to non-sterile conditions. The effect of vermiculite substrates and their mixtures on the survival rate and growth of plants was studied. The use of TV2-N substrates and a mixture of TV2-N with soil contributed to an increase in the survival rate of plants compared to plants grown in soil. For plants grown on these substrates, 100% survival rate was established. When using a mixture of these substrates with soil, a decrease in this indicator to 95-90% was observed, with the greatest losses in the number of plants that took root in the variant when grown in soil (survival rate of 76%). Plants grown on a mixed substrate of thermovermiculite TV2-N and soil were 40% taller than those grown in soil (control plants). They also had a 22% higher crude biomass value and 95% greater root mass than the control plants. The growth of plants and crude root biomass in plants grown on the TV2-N substrate was 16% and 30%, respectively, compared to the control plants. No statistically significant differences were found in these plants in terms of crude biomass. The use of Vipon-2 substrates and a mixture of Vipon-2 with soil for growing regenerants turned out to be less effective than the TV2-N substrate for obtaining taller plants with greater biomass. Nevertheless, the root mass of plants grown on the Vipon-2 substrate and a mixture of Vipon-2 with soil was 30% greater than that of the control plants. The obtained data indicate the potential of using substrates based on thermovermiculite for the adaptation of regenerated pineapple strawberry plants to non-sterile conditions during the transition from in vitro to ex vitro conditions.