Somatic hybrid plants of Nicotiana glauca and Nicotiana tabacum obtained by protoplast fusion

Abstract Somatic hybrid plants were produced by fusion of protoplasts from cell cultures of the Nicotiana tabacum L. sulfur mutant Su/Su and from leaf mesophyll of Nicotiana glauca Graham. After fusion the N. glauca protoplasts failed to survive under the selected culture condition. From the hybrid cells light green shoots were produced. The hybrid plants exhibited intermediate characters between parental species with respect to leaf morphology, trichome density, floral structure and flower color. The chromosome number of 25 hybrid plants was 2n = 72 and both N. glauca and N. tabacum chromosomes were identified in the hybrids. Results of isoenzyme analysis showed bands of both parents and a specific (hybrid) band for aspartate amino‐transferase. Small subunit fraction‐1‐protein of somatic hybrids also consisted of the sum of N. glauca and N. tabacum bands. Leaf spot formation associated with the Su locus of N. tabacum was observed in somatic hybrids.