Screening for Ralstonia solanacearum Resistance in Solanum commersonii

Abstract

Worldwide, potato (Solanum tuberosum L) is rated as one of the most important food crops after wheat, rice and maize. Bacterial wilt, caused by Ralstonia solanacearum (Rs), is one of the most economically important diseases of potato. The purpose of this study was to identify diploid germplasm with resistance to bacterial wilt. The wilting degree was assessed by analyzing the wilt percentage of six Solanum commersonii clones which were artificially inoculated with Rs in a growth chamber. Two Rs strains (CMR15 and UW551) were used to inoculate the clones evaluate resistance. MSEE912–08, a selfed progeny from PI320266 was identified as the most resistant of the clones in this study exhibiting the lowest RAUDPC for wilting and a Wilting Degree rating of 0.4 (less than 25% wilted leaves) 20 days post inoculation when inoculated with the UW551 Rs strain, and 1.3 with the CMR15 strain. The resistance observed was characterized by reduction in wilting over time, rather than lack of disease. The most resistant clone from this study was self-pollinated to create a mapping population to identify single nucleotide polymorphic (SNP) markers associated with Rs resistance.