INTERSPECIFIC HYBRIDIZATION FOR LEEK (ALLIUM AMPELOPRASUM) IMPROVEMENT

In leek (Allium ampeloprasum) several important breeding traits are missing that are present in other cultivated Allium species. The high crossing barriers between leek and species of subgenus Rhizirideum have been overcome to introgress new traits from other cultivated Alliums. Interspecific hybridizations to common onion (A. cepa), Japanese bunching onion (A. fistulosum), and chives (A. schoenoprasum) were carried out to contribute to the improvement of leek. GISH and FISH techniques as well as molecular markers have been applied to characterize the mitotic chromosomal constitution and the meiotic behaviour of hybrids and their derivatives. To open the chance for a CMS system in leek, a sexual hybrid between a cytoplasmic male-sterile onion and leek was used to transfer the alien cytoplasm into leek. The phenotype of alloplasmic leek is modified in comparison to euplasmic leek suggesting some incompatibility between T-cytoplasm of onion and leek genomes. Addition of onion chromosome 1C conferred normal growth of the alloplasmic leek. The hybridization between Bunching onion and leek could be useful both for transferring a new cytoplasm for CMS induction and to introgress genomic components transmitting resistance. An A. fistulosum x A. ampeloprasum hybrid (FAA, 2n=24) was produced by means of embryo rescue and the hybrid chromosome number was doubled with colchicine. Hybrid plants from crosses A. schoenoprasum x A. ampeloprasum were obtained.