Characterization of Interspecific Hybrids between Allium ascalonicum L. and A. cepa L.

Characterization of interspecific hybrids between Allium ascalonicum (shallot) and A. cepa (onion) and their backcross progeny including investigation of mitotic and meiotic chromosomes were conducted. Interspecific pollination was made with a male sterile shallot line as a pistillate parent and a male fertile onion line as a pollen parent. BC₁F₁ families were generated by crossing selected male fertile F₁’s to male sterile shallot or male sterile F₁’s to male fertile onion. Relative seed setting ratios in an umbel to onion intraspecific pollination were 22.8% in the initial shallot × onion cross, 17.1% in the backcross of F₁ to onion and 50.3% in the backcross of F₁ to shallot. Chromosome pairing at metaphase I of meiosis was almost perfect but configuration of bivalents differed somewhat by parental combinations. The interspecific hybrids were intermediate of the parental species in shape and size of bulbs, flowering time and shape of florets.