Screening Red Raspberry (Rubus idaeusL.) Germplasm for Freeze Tolerance in Norway

Abstract

Abstract Freeze tolerance of red raspberry cultivars and selections, including one specimen each from eight indigenous Norwegian Rubus idaeus L. populations, showed that there were significant differences in bud survival and tissue browning in a two-year test at Stj⊘rdal, Norway. Selections from the Norwegian breeding program and the Norwegian cultivar Balder had the most freeze-tolerant buds at the May screening in both years, while the Norwegian cultivar Vene was tolerant in one year. The cultivars Malling Admiral, Nootka, Chilcotin, Glen Isla and Gradina were tolerant in one of the years but not in the other. Meeker, Glen Moy, Skeena, Glen Prosen, Malling Joy, Malling Leo and Malling Orion were not tolerant in either year. The selections from indigenous Norwegian Rubus idaeus were all freeze-tolerant in one year, but less tolerant than the best the other year. Tissue browning was preferred as a screening test for freeze injury in midwinter, while bud growth is preferable in spring.