Patent ID: 8779234

Claim:
An onion or shallot plant of Allium cepa species which is resistant to downy mildew of onion caused by the fungus Peronospora destructor (Pd), which plant comprises a Pd resistance locus, conferring resistance to downy mildew of onion, present homozygously in the long arm of chromosome 3 in the genome of said plant, wherein the Pd resistance locus comprises (i.) a 61 nucleotide amplification product with the selective amplification primers 5′-GACTGCGTACATCCAGAAC (SEQ ID NO:5) and 5′-GATGAGTCCTGAGTAACTT (SEQ ID NO:6), or (ii.) a 151 nucleotide amplification product with the selective amplification primers 5′-GACTGCGTACATGCAGAAG (SEQ ID NO:7) and 5′-GATGAGTCCTGAGTAAAAC (SEQ ID NO:8), or (iii.) a 330 nucleotide amplification product with the selective amplification primers 5′-GACTGCGTACATGCAGACA (SEQ ID NO:9) and 5′-GATGAGTCCTGAGTAACCA (SEQ ID NO:10), in the genome of said plant restricted with restriction enzymes PstI and MseI; and ligated with the following oligonucleotide adapters: alpha 5′-CTCGTAGACTGCGTACATGCA (SEQ ID NO: 1) CATCTGACGCATGT-5′, (SEQ ID NO: 2) and beta 5′-GACGATGAGTCCTGAG (SEQ ID NO: 3) TACTCAGGACTCAT-5′; (SEQ ID NO: 4).