Identification of a Gene Conferring High Levels of Resistance to Verticillium Wilt in Solanum chacoense

Abstract

Verticillium wilt (Verticillium albo-atrum) is an important disease affecting potato tuber yield and quality. In North America the major commercial cultivars are susceptible and management strategies for control of the pathogen rely mainly on soil fumigation and crop rotation. In this study 398 genotypes from accessions of Solanum berthaultii, S. chacoense, and S. tarijense were screened for resistance to Verticillium albo-atrum. Resistant genotypes were identified in all but two accessions; however, results indicate that tolerance is more common than resistance. We identified two genotypes in S. chacoense (PI 472819) that had low stem-colonization levels and also did not develop wilt symptoms when inoculated with V. albo-atrum. These genotypes and a susceptible genotype from PI 472810 (S. chacoense) were studied to determine genetic inheritance. Segregation ratios in F1, F2, and backcross populations indicated that resistance in one of the resistant genotypes (18-21R) was controlled by a single dominant gene. Transfer of the Vc gene to tetraploid germ plasm could provide effective and economical control of Verticillium wilt.