Reactions of strawberry plants to long-term freezing and alternate freezing and thawing

The study was conducted in two experiments, one examining the effects of al ternate freezing and thawing at -12 degreesC for 2 h and +6 degreesC for 24 h, and the other examining the effects of permanent freezing for 1 or 15 d at -12 degreesC. In both experiments the plants were grown in the pre-frui ting period at a coastal or a continental location in Norway. The freezing injury increased the higher the stress, indicated by reduced growth, fruit size and yield. It was shown that 'Korona' was the most hardy cultivar at a short period of freezing stress and at alternate freezing and thawing, whi le 'Senga Sengana' was more freezing tolerant at long-term permanent freezi ng than 'Bounty' and 'Korona.' In general the results indicate that the pla nts induce freezing tolerance according to some factor of origin, since pla nts grown in the continental climate were better able to survive long-term permanent freezing than plants grown in a coastal climate, and plants grown in a coastal climate were better able to survive alternate freezing and th awing than plants grown in a continental climate.