The present invention relates to plants of the genus Allium, specifically plants of the Allium cepa or Allium fistulosum 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 or Allium fistulosum species which are resistant to downy mildew of onion caused by the fungus Peronospora destructor (Pd) due to a Pd resistance locus present homozygously in the genome of said plants. The present invention also provides processes for obtaining said plants resistant to downy mildew of onion, said processes being suitable for obtaining cultivated onions and shallots.
