Monohibrid Dominant Inherentanceof TMV Resistance in Some Oriental Varieties of Yaka Tobacco

Investigations were made on the inheritance of resistance to tobacco mosaic virus (TMV) in some oriental tobacco varieties by the method of interspecies hybridization. The selection process started with crossing of TMV resistant varieties (AA) with non-resistant aromatic varieties of the type Yaka. In F1, TMV resistance was inherited dominantly, or the obtained plants were heterozigous (Aa). From self-pollinated hybrids of F1 generation, the plants obtained in F2 were varying in their genotypes in 3 : 1 ratio ( 3 resistant : 1 non-resistant plants). Genetic formula of the resistant plants is (AA), (Aa) and (Aa). When inoculated with infective sap, plants show necrotic reactions, which indicates that the investigated trait was dominant. In F2 generation a number of resistant plants were selected to create separate progenies in F3. Inoculation was carried out with infective sap from diseased plants, using the method of Ternovsky (1965, cit. by Tran?eva, 1995). The aim of the paper was to study the mode of inheritance of TMV resistance in creation of new varieties of Yaka tobacco.