V. Ilcheva et al., Morphological and cytological characteristics of somatic hybrids of Nicotiana tabacum L-(+) N-megalosiphon Heurk. et Mull., IN VITRO-PL, 36(1), 2000, pp. 69-73
Somatic hybrid plants of Nicotiana tabacum (bar) (+) Nicotiana megalosiphon
(npt II) were recovered after polyethylene glycol (PEG) mediated fusion. H
ybrid calluses were selected on the basis of their dual resistance to biala
phos and kanamycin or UV inactivation of the donor species (Nicotiana megal
osiphon) protoplasts. The hybrid nature of the individual clones obtained w
as confirmed by AFLP analysis. An array of plants were recovered including
self-fertile hybrid plants with N. tabacum or N. megalosiphon phenotype, se
lf-sterile plants with N. tabacum habit, leaf and intermediate flower morph
ology, self-sterile plants with N. megalosiphon habit, abnormal leaves and
intermediate flowers, and self-sterile plants of N. megalosiphon type with
abnormal characters. Viable pollen was observed in hybrid plants from the t
hird group. The hybrids possessed a nuclear DNA content near that of the di
ploid tobacco or N. megalosiphon, and also near that of the tetraploid geno
me size of N. megalosiphon. The results provide evidence for nonpreferentia
l loss of one of the parental genomes and spontaneous asymmetrization of hy
brid plants. The present study shows that by means of somatic hybridization
a great genetic diversity in the hybrid clones can be achieved.