Closing Notes on Interspecific Hybridization in Tobacco Improvement

Nicotiana tabacum is phylogenetically a relatively young form. With the possible exceptions of N. arentsii and N. rustica, the other direct ancestors of the present-day Nicotiana species completed their evolution much earlier than N. tabacum. In pre-Columbian America, several species were grown by the natives and attempts may have been made to improve them by selection, but interspecific crossing in those ancient times seems unlikely. It took several hundred years after the discoveries of the New World before the first hybrids between species of Nicotiana were created. The brief review looks back on the eventful period in the history of interspecific hybridization and introgression in tobacco between the 1930s and late 1070s when most of the interspecific hybrids were made and the most momentous interspecific gene transfers were accomplished, most of them without resorting to biotechnological and molecular methods available now. Subsequent paragraphs briefly sum up the present developments in Nicotiana science and important gene transfers that have been made. Attention is drawn to the possibility that many cases of introgression from wild Nicotianae may have passed unnoticed and that it is difficult to estimate to what extent Nicotiana species have actually contributed to present-day usable tobacco genotypes. The review concludes expressing hope that tobacco and the Nicotiana species will continue at the forefront of plant and crop science.