Bull. Spec. CORESTA Congress, Brighton, 1998, p. 145, PPOST05

Using haploidy by androgenesis and embryoculture in tobacco breeding

Central Research Station for Tobacco Culture and Industrialization, Bucharest, Romania.
In order to fulfill the main purposes of tobacco breeding (high yield potential, superior chemical and industrial quality, resistance to the main diseases of tobacco), the creation of a large genetic variability is needed. The classic methods for the creation of this genetic variability are not sufficient, presenting certain genetic limits such as that of sexual incompatibility between different species, the species of the genus Nicotiana representing the main source of genetic resistance to the diseases of tobacco. The up-to-date methods, such as the haploidy by androgenesis and embryoculture, used in tobacco breeding, allow the surpassing of these limits and the achievement of valuable genotypes that can be used as parents in the breeding process. The use of haploidy by androgenesis allow to obtain a large number of isogenic lines for Oriental, Virginia and Burley tobacco. These lines have been tested in the period 1995-1997 in comparative cultures, having in study especially the morphological and physiological traits, the yield potential and the chemical and industrial quality. The results obtained have shown that eleven lines (Djebel 664, Djebel 656, Molovata 86, Molovata 588, Virginia 812, Virginia 819, Virginia 991, Virginia 983, Burley 884, Burley 852 and Burley 858) proved to be valuable both from the point of view of yield potential and chemical and industrial quality or precocity. The method of embryoculture allowed to obtain a large number of hybrids between species, between tobacco cultivars (Oriental, semi-oriental-Ghimpati, Virginia and large-leaved tobacco) and the wild species: Nicotiana alata, Link et Otto, Nicotiana sanderae , Hort and Nicotiana longiflora , Cav. These hybrids between species are in the stage of fertilisation, using for this different methods in vitro and the influence of different chemical substances for doubling the set of chromosomes.