N. africana was crossed with diploid and tetraploid N. tabacum to study the wild species' potential as a source of resistance to TSWV. Germinating seeds were obtained from mating female N. tabacum with male N. africana but the seedlings usually failed to grow beyond the cotyledonary stage. Cotyledon segments were cultured in vitro to induce callus formation and shoot regeneration. The method yielded vigorously growing plants which belonged to three cytological categories : practically self-and cross-stertile amphihaploids, partically self-and cross- fertile sesquidiploids and self- and cross-fertile culture- induced doubled amphihaploids (amphidiploids). The study of meiosis in the amphihaploids revealed variable low pairing with the number of bivalents from 0 to 5. Regular pairing was restored in the doubled amphihaploids. The plants of N. africana , sesquidiploids, and the selfed progeny of the sesquidiploids (S1) were tested for resistance to TSWV using artificial inoculations in the greenhouse. All N. africana plants and 80% of the amphihaploids showed no visible symptoms of the disease and in the remaining 20% the symptoms developed long after the N. tabacum controls had died. Over 95% of the S2 developed TSWV symptoms. Somatic fusion of N. africana and N. tabacum is conducted alongside and the fusion products will be included in the breeding program.