Frost Hardiness and Cold Acclimation in Solanum Species

Abstract

Potato is the world’s fourth most important crop, however, it ranks first in the yield per unit of land among the world’s major food crops (F.A.O. Production Year Book, 1991). It is mainly grown in the temperate zone and in the highlands of the Andean Tropics of South America, where frosts are often the major factor in reducing the yield and quality of potato crops. For example, in the Andean countries alone, it is estimated that over 400,000 ha of potato field are threatened by frost injury every year (Vega and Bamberg, 1995; Van Eck, 1995; Estrada et al., 1993; Barrientos et al., 1994). The commonly cultivated potato, Solanum tuberosum, possesses little frost hardiness, whereas many of the tuber-bearing Solanum species are much hardier than S. tuberosum. It would be desirable to combine the higher yield potential of S. tuberosum with the frost hardiness traits from the hardy relatives. However, efforts to transfer frost hardiness genes from wild species to cultivated S. tuberosum by conventional breeding have been proven possible but likely a lengthy process (Estrada, 1987; Estrada et al., 1993).