The wi gene causes genic male sterility in Allium choenoprasum

Segregation studies following the transfer of the gene wi to different cytoplasm types, which have been distinguished by means of restriction fragment length polymorphism analyses using mitochondrial gene probes, revealed the formation of the wi‐sterility in each of the four cytoplasms examined. The male sterility is therefore only caused by the nuclear wi gene, i.e. an additional factor of a specific cytoplasm can be excluded. Hence, the wi‐sterility proved to be a genic male sterility (GMS) and not a cytoplasmic male sterility (CMS). The expression of the wi‐sterility appears to be stable, since it is not affected by high temperatures or tetracycline. Accordingly, a temporary pollen production, which would allow self‐fertilization for the maintenance of sterile lines, cannot be induced by controlling these environmental factors. In terms of hybrid breeding, this GMS therefore has no advantage over the previously described CMS system.