Cytogenetic analysis of interspecific sunflower hybrids and molecular evaluation of their progeny

Meiotic cells of transgenic asymmetric somatic hybrid (ASH) plants obtained by fusion of microprotoplasts of the donor species Helianthus giganteus or Helianthus maximiliani and recipient protoplasts of Helianthus annuus were investigated. Over 85% of the ASH meiocytes showed regular bivalent chromo some pairing; however, several anomalies like anaphase bridges, laggard chr omosomes, univalent and multivalent pairing were also observed. Pollen viab ility of the ASH plants ranged from 79.2 to 95% with a strong negative corr elation to chromosome number which varied between 34 and 42. Molecular inve stigation of ASH progeny using RAPD markers revealed the presence of donor genotype markers in 68% of the offspring. These results suggest that asymme tric somatic hybridization offers an efficient alternative method to overco me sexual barriers for gene flow and the genetic improvement of H. annuus b y introgression of economical important traits from wild Helianthus species .