CHARACTERIZATION OF SOMATIC HYBRIDS BETWEEN SOLANUM-TUBEROSUM AND ITSFROST-TOLERANT RELATIVE SOLANUM COMMERSONIL

Somatic hybrids between three dihaploid Solanum tuberosum (2n = 2x = 2 4) genotypes and the frost-tolerant, diploid, relative Solanum commers onii (2n = 2x = 24) were analysed for variation in morphological trait s, fertility and frost tolerance. The somatic hybrids were more vigoro us than their parents and in many ways resembled a tetraploid S. tuber osum. All of the hybrids flowered profusely, although the male fertili ty was largely dependent on the S. tuberosum genotype used. In one hyb rid combination ail plants were both male- and female-fertile, while i n the other two combinations the majority of plants were male-sterile but female-fertile. The somatic hybrids showed an increase in direct f rost tolerance when compared with the dihaploid S. tuberosum parents, and to a varying extent had gained the capacity to cold acclimate. The se somatic hybrids will be used in breeding programmes involving repea ted cycles of anther culture and somatic hybridisation.