An Alternative Strategy for Clonal Micropropagation of the Garden Strawberry

The aim of the study was to develop a technological approach for the production, storage, and preparation of strawberry microplants, facilitating their simultaneous acclimatization before planting in a greenhouse when favorable temperature and lighting conditions are established.

The initial material for the experiment was obtained via clonal micropropagation. Preparation, accumulation, and preservation of strawberry plants in vitro for delayed acclimatization were performed by periodically repeating the procedure of removing roots and leaves from previously rooted microplants and transferring them in the form of vegetating buds onto a fresh nutrient medium for further rehabilitation. The mass acclimatization of microplants was carried out under substrate-free flow-through hydroponic conditions, following which they were transplanted into a greenhouse in early spring.

The survival rate of microplants during the periodically repeated procedures of removing roots and leaves from previously obtained microplants reached 100% for all studied cultivars. Active leaf and root recovery began on days 3–7 and 10–14, respectively. A 1-month acclimatization period on flow-through hydroponics allowed for a 2–2.5-fold increase in microplant height, a 2-fold increase in root length, and an almost 3-fold increase in weight.

The repetitive removal of microplant roots and leaves, with their further transplantation on fresh nutrient medium as vegetating buds for subsequent rehabilitation during periods of unfavorable environmental conditions, does not reduce the viability of microplants, allowing the preservation of planting material without loss until acclimatization is advisable. Acclimatization using flow-through hydroponics enables the elimination of fungal pathogenesis that occurs during the use of solid substrates. This protocol also increases the predictability of acclimatization outcomes and ensures successful transplantation into a greenhouse.

The developed alternative strategy of strawberry clonal micropropagation allows prediction of the output volume of acclimatized microplants throughout a calendar year with a high degree of accuracy. The estimated quantity of such material can be compactly stored in a lighted tissue culture room, significantly saving time and resources. Microplants are well preserved until a favorable moment for acclimatization in a viable state as vegetating buds. After the rehabilitation cycles are complete, the microplants can be simultaneously transferred for acclimatization on flow-through hydroponics.