Interspecific hybrids between onion (Allium cepa L.) with S-cytoplasm and leek (Allium ampeloprasum L.)

 Interspecific hybrids between Allium cepa and A. ampeloprasum have been generated as a first step for the introduction of S-cytoplasm from onion into leek. Pre-zygotic barriers of crossability were observed after the arrival of pollen tubes at the end of the style when entering the cavity. Nevertheless, micropyle penetration of pollen tubes and the formation of hybrid embryos were also observed. After accomplishing in vitro culture of ovaries and ovules successively, triploid hybrid plants with 24 chromosomes were obtained. Their hybrid nature was confirmed by RAPD analysis, genomic in situ hybridization, and morphological analysis. Southern hybridization with a cytoplasmic probe indicated the transfer of unaltered S-cytoplasm into the hybrid plants. Received: 9 May 1996 / Accepted: 23 August 1996