Mapping the H2 resistance effective against Globodera pallida pathotype Pa1 in tetraploid potato

Abstract: The H2 resistance, introduced into cultivated potatoes from the wild diploid species Solanum multidissectum, confers high level of resistance to the Pa1 pathotype of the potato cyst nematode Globodera pallida. A cross between tetraploid H2-containing breeding clone P55/7 and susceptible potato variety Picasso yielded an F1 population that segregated nearly 1:1 for the resistance phenotype and which is consistent with a single dominant gene in a simplex configuration. Using genome reduction methodologies RenSeq and GenSeq, the segregating F1 population enabled the genetic characterisation of the resistance through a bulked segregant analysis. RenSeq and GenSeq independently identified sequence polymorphisms linked to the H2 resistance on the top end of potato chromosome 5. Allele specific KASP markers further defined the locus containing the H2 gene to a 4.7Mb interval on the distal end of potato chromosome 5 and to positions that correspond to 1.4MB and 6.1MB in the potato reference genome, respectively.