LONG-TERM MAINTENANCE OF STRAWBERRY PLANTS IN-VITRO

The effects of the components of nutrient medium on strawberry (Fragar ia L.) plant maintenance in vitro were studied. The life span of a str awberry plant during one subculture can be extended by introducing man nitol into Murashige and Skoog medium and substituting calcium chlorid e with calcium nitrate (8 - 12 mM). A modification of agar-solidified nutrient medium suitable for long-term maintenance 20 strawberry meric lones is proposed. At a temperature of 25 - 28-degrees-C and illuminat ion of 5 - 8 klx during 16-h light periods, more than 50% of the plant s from this collection remained viable on this nutrient medium during an eight-month period. At a temperature of 2 - 4-degrees-C and illumin ation of 0.5 - 0.8 klx during four-hour light periods, more than 60% o f the plants were alive for 24 months.