Detection and Heritability of Genes Conferring Resistance to Potato Pests and Viruses in Hybrid Potato Progeny (Solanum tuberosum L.)

Potato viral infections are among the main factors contributing to reduced quality of planting material and decreased tuber productivity. Currently, no reliable chemical control methods are available for plant viral diseases. Therefore, the development of potato cultivars carrying virus resistance genes remains one of the most effective and comprehensive approaches to this problem. In this study, 29 Russian and foreign potato cultivars, as well as 31 Far Eastern potato hybrids were evaluated. Resistance genes were identified using PCR analysis. The following cultivars carrying target resistance genes were used as positive controls for method calibration: Meteor (Rysto, Rx1, Sen1, Gpa2, H1), Vektor (Rx1, Gpa2), Yubilyar (Gpa2), and Zhukovsky ranniy (Gpa2, Rx1). Method calibration enabled determination of optimal magnesium chloride concentrations: 2.0 mM for Gpa2 and 2.5 mM for Rx1. Genotyping of 29 potato cultivars identified several highly resistant accessions, including Yubilyar, Zhukovsky ranniy, Bellarosa, Sante, Smak, Red Scarlett, and Laperla. These cultivars combined resistance to Potato virus X (Rx1) with complex resistance to two nematode species (Gpa2, H1). In the studied population, high frequencies of the Gpa2 (82.8%) gene and the H1 (65.5–69.0%) gene group were observed. Statistical analysis provided strong evidence for tight genetic linkage between the Rx1 and the Gpa2 loci on chromosome 12. The association was highly significant (p < 0.001). Analysis of 31 potato hybrids revealed 14 multi-marker genotypes with high breeding potential. A stable combination of five target resistance markers was consistently detected in their genomes. A dominant hybrid family derived from the Yantar × Smak cross was identified, represented by five related lines. For the first time, a precise heritability coefficient was calculated for the STS marker of the Rx1 gene in a Far Eastern hybrid population. The estimate reached h2 = 0.835 at p = 0.01. This value significantly exceeded the critical threshold for breeding reliability (h2 > 0.7), indicating largely additive genetic control of the trait. These results support targeted selection of parental combinations for breeding programs aimed at improving virus and nematode resistance in potato.