The present invention relates to plants of the Allium cepa species, which are resistant to the downy mildew of onion caused by the fungus Peronospora destructor, due to a Pd resistance locus, wherein any fragment of a chromosome, comprising the Pd resistance locus, can be present homozygously in progeny without causing lethality. The present invention also encompasses plants of the Allium cepa species which are resistant to downy mildew of onion caused by the fungus Personospora destructor (Pd) due to Pd resistance locus present homozygously in the genome of the plants. The present invention also provides processes for obtaining plants resistant to downy mildew of onion, which are suitable for obtaining cultivated onions and shallots.
