Studies of potato resistance to revealed novel alleles for 57R marker.

resistance has been an important trait in potato () breeding for decades. Our aim was to complement phenotypic testing with genetic marker analysis. We analysed the results of resistance greenhouse testing in 4601 tubers of 2918 breeding clones from 11 years. Applicability of gene markers TG689 and 57R was compared. We implemented the latter with the positive predictive value of 99.1% and negative predictive value of 60.0% into the breeding scheme. The 57R marker alleles of 22 Estonian cultivars and 470 breeding clones were determined. Two unique 57R alleles, 57R-887 and 57R-1155, were found in Estonian cultivar 'Anti'. The 887 bp allele has two deletions (14 bp and 490 bp) accompanied by several other indels and SNPs within the 57R marker region. The 1155 bp allele has three deletions (7 bp, 20 bp and 210 bp) accompanied by several other indels and SNPs within the same region. Partial resistance to in 'Anti' suggests that the newly described alleles could affect the -mediated resistance directly or indirectly.