Bull. Spec. CORESTA Symposium, Kallithea, 1990, P. 142, 142, ISSN.0525-6240

Transfer of cytoplasmic male sterility to Nicotiana tabacum L. by protoplast fusion

Institute of Genetics, Sofia, Bulgaria. Institute of Plant Physiology. Szeged. Hungary.
Protoplast fusion was used for producing cytoplasmic male sterile (CMS) tobaccos within a shorter period of time (one year) than the conventional backcross method, for which several years are required. Mesophyl protoplasts of CMS line (N. tabacum cv. Charmanliska basma with cytoplasm from N. maritima) were irradiated by 60Co to inactivate their nuclei. They were fused with untreated protoplasts of fertile N. tabacum cv. Ludogoretz, using polyethylene glycol (PEG). 38 CMS plants were found among 53 regenerants. The cytoplasmic marker was used to distinguish the hybrids displaying the nuclear phenotype of the cv. Ludogoretz associated with a modified flower type of the CMS line. Their chromosome number ranged from 46-48 (expected 2n = 48). The cytoplasmic character of the male sterility was maintained in the progeny obtained from backcrosses with normal fertile Ludogoretz pollen.