Use of ovule culture to cross between Delphinium species of different ploidy

The applicability of ovule culture was examined in reciprocal crosses between the diploid species D. grandiflorum L. and the tetraploid cultivar D. hybridum `Galahadʹ. An interspecific hybrid plant of D. hybridum `Galahadʹ × D. grandiflorum was obtained, and hybridity was confirmed by chromosome counting. The hybrid was different from the parents in flower color and size but intermediate between the parents in leaf shape. The hybrid showed low pollen fertility and failed to produce viable seeds by either self- or backcross-pollination using fertile pollen grains from its parents. The applicability and efficiency of the ovule culture technique for genetic improvement of the genus Delphinium through interspecific hybridization between different ploidies is discussed.