COLD-STORAGE OF STRAWBERRIES INVITRO - A COMPARISON OF 3 STORAGE-SYSTEMS

Three storage systems used for strawberry in vitro germplasm conservation were compared for plant health, culture longevity and frequency of contamination following storage at 4-degrees-C. Storage systems using 16 mm glass tubes, 6 x 6 x 9 cm plastic boxes and 5 chamber plastic bags were analyzed for longevity and contamination rates. Ninety-six accessions cold hardened and stored in polyethylene bags showed a greater average longevity than 127 non-hardened plantlets stored in plastic boxes. After 12 months, 76% of accessions in bags remained viable in storage in contrasts with 42% in boxes. Storage of 130 Fragaria plantlets in 16 mm glass tubes resulted in 20% survival after 24 months of storage. The contamination rate for tubes was 47%, boxes 30% and bags 10%. Contamination in bags was confined to a single plant in one chamber of a five chamber bag, however, contamination in boxes and tubes usually involved all plants in that container. The bag system was superior to boxes and tubes for preserving stored plants and excluding contamination and provides a good choice for germplasm conservation.