Abstract
A dominant gene Ws(pbg) of Nicotiana plumbaginifolia covers the effect of a recessive allele ws of N. tabacum which conditions an inability of chlorophyll production. As.. additional plumbaginifolia chromosomes are somatically unstable in tabacum nucleus, the hybrid plants are usually mottled. Soaked seeds of a hybrid derivative plant of which chromosome constitution was 24. pairs of tabacum chtomosomes (ws ws) plus one plumbaginifolia chromosome ( Ws(pbg)) were irradiated by 5.000 R of X-ray. Self green sectors and leaves were observed insome mottled X1 plants. Some of the X1 plants were branched and self green leaves, were developed on one of the branches. Meiotic configurations of these X1 plants andsegregation ratio for leaf color in X2 generation proved that the self green sectors and leaves were due to interspecific translocations of Ws(pbg) . It was observed that an inflorescence of some X1 plant was genetically heterogeneous. The transmissipn rateof Wg(pbg) translocated to tadacum chromosome rec. iprocally was very low. The rate of the induced translocation of Ws(pbg) was about 5%.
