Transgenesis allows the modification of plant genomes relatively quickly and precisely. Moreover, compared with classical methods, genetic transformation significantly facilitates and shortens the time needed for breeding a new cultivar. Shortening a breeding process is possible thanks to obtaining haploids and then doubled haploids being homozygotes as regards all traits, which increases the efficiency of selection of desired recombinants.

The plant material used in the study consisted of transgenic tobacco lines containing lettuce mosaic virus coat protein gene (LMV CP) determining resistance to potato virus Y (PVY). Doubled haploids were obtained by combination of anther culture and spontaneous doubling of the number of chromosomes under in vitro conditions. The generation DH₂ of doubled haploid lines, obtained from hybrids coming from crossing transgenic cultivar MN 944 with cv. Wislica and hybrids obtained from crossing transgenic cv. BY 103 and its nontransgenic equivalents, were estimated by comparison with their parental cultivars. The experiment was conducted under greenhouse conditions. The evaluation of agronomic traits included elements of growth and development such as growth rate, length of vegetative and generative stages, area of leaves, height and morphology of plants. Cured leaves of DH lines were analysed as regards selected physical and chemical traits. Moreover, the pollen viability was estimated.

Individual DH lines differed among themselves and in comparison to parental cultivars as regards some traits. However, only little diversity within the lines was noticed. The DH lines characterized by the most satisfying agronomic traits may be valuable initial material in further breeding.