Creation of Clones with Multiple Multiplexed Resistance Genes Useful in Potato Breeding

Abstract To broaden genetic diversity in the breeders’ gene pool, we previously selected 95 long-day-adapted hybrid clones from Andean cultivated potatoes. In this study, these clones were crossed to combine resistance genes for golden cyst nematode ( H1 ), Potato virus Y ( Ry chc ), and Potato virus X ( Rx1 ) into individual clones using marker assays through multiplex PCR. Additionally, effective late blight resistance genes, Rpi-blb3 and/or R2 , were incorporated. After field evaluation, the selected clones were crossed and marker-assayed with real-time PCR to increase the copy number (dosage) of the resistance genes. After two rounds of increasing the copy number, 16 clones exhibited an average copy number of 3.00 for H1 , 2.56 for Ry chc , and 2.81 for Rx1 , while 18 clones showed an average copy number of 2.56 for H1 , 1.94 for Ry chc , and 2.06 for Rx1, along with 0.83 for Rpi-blb3 and 0.61 for R2 . These 34 clones possess multiple, multiplexed resistance genes, which are valuable for breeding programs.