Reproducible Quantitative Trait Loci for Resistance to Soft Rot Caused by Derived from the Wild Potato (PI 458355) Are Located on Chromosomes 1, 3, and 5.

The potato wild relative is a breeder-friendly source of genetic resistance to soft rot. Our objectives were to (i) identify loci associated with soft rot resistance in germplasm and (ii) develop bi-parental populations in a self-compatible genetic background to recover segregating F progenies, construct a linkage map, and identify quantitative trait loci (QTLs). Under objective (i), tubers from 103 genotypes from the United States Potato Genebank were inoculated with a high virulence strain of , and lesion size was measured after a 24-h incubation period at 30°C. Association analysis using 3,490 polymorphic Infinium array SNP markers identified soft rot resistance loci on chromosomes 1, 2, 3, 5, 7, 8, 11, and 12. Under objective (ii), a resistant accession PI 458355 was crossed with a highly fertile, self-compatible, diploid pollen parent (PI 654351) to generate segregating F populations. Composite interval mapping was conducted using a genetic linkage map with 970 GBS-based SNP markers. Reproducible QTLs were detected on chromosomes 1, 3, and 5, explaining 11, 13, and 23% of the phenotypic variation, respectively. Homozygous alleles at the QTL on chromosome 5 and heterozygous or homozygous alleles at QTLs on chromosomes 1 and 3 significantly decrease lesion size compared with the homozygous parent. The germplasm created in these studies provides a resource for studying traits from , and we can use the advanced F selections for future potato improvement. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.