Resistance to Bacterial Wilt in Solanum commersonii Dun

The levels of resistance to bacterial wilt (BW) of potatoes caused by Ralstonia solanacearum (Rs) are limited. Solanum commersonii (cmm) is a wild tuber-bearing potato highlighted for its resistance to BW. This research aimed to (i) characterize cmm genotypes for resistance to Rs (race 3, biovar 2) using a soil inoculation method, (ii) determine to what extent resistance in cmm is transmissible through sexual reproduction to a susceptible genetic background, and (iii) determine the relationships between a set of Rs strains (race 3, biovar 2) and cmm genotypes in the expression of resistance. The screening was performed under controlled conditions of temperature and light. Accessions collected from different regions of Uruguay showed diversity for resistance to BW: some genotypes were asymptomatic in the response, while for others the symptoms were similar to the susceptible control. Two cmm genotypes with contrasting responses to BW were crossed, and an offspring of 121 genotypes was obtained. The distribution of BW resistance levels in the progeny suggested a polygenetic control for BW resistance; though this conclusion is preliminary regarding that one of the cmm parents was triploid. A factorial experiment using five R. solanacearum strains isolated in Uruguay and five cmm clones showed differences in the virulence between strains. There was no interaction between plant genotype and bacterial isolate, and therefore, under the conditions of this research, BW resistance in cmm was not dependent on the isolate of the pathogen. Los niveles de resistencia a la marchitez bacteriana (MB) de la papa causada por Ralstonia solanacearum (Rs) son limitados. Solanum commersonii (cmm) es una especie silvestre destacada por su resistencia a MB. Los objetivos de este trabajo fueron (i) caracterizar genotipos de cmm para resistencia a Rs (raza 3, biovar 2) utilizando un método de inoculación en suelo, (ii) determinar en qué medida la resistencia de cmm es transmisible por vía sexual en un trasfondo genético susceptible, y (iii) determinar la relación entre un grupo de cepas de Rs raza 3 biovar 2 y genotipos de cmm en la expresión de la resistencia. Se utilizó una metodología de inoculación en suelo bajo condiciones de temperatura y luz controladas. Para genotipos de cmm colectados en distintas regiones de Uruguay, se encontró variabilidad en la resistencia a MB, desde respuesta asintomática en algunos genotipos hasta síntomas en nivel similar al control susceptible. Med