Breeding for resistance to tomato bacterial wilt: Identification of potential sources of genetic resistance by field evaluation of 28 tomato cultivars in Daloa, Côte d’Ivoire

Abstract

Bacterial wilt caused by Ralstonia solanacearum is one of the most damaging tomato diseases in the world. The best strategy for controlling this disease is to use genetically resistant tomato plants. In this study, 28 tomato cultivars were evaluated in the field for their resistance to bacterial wilt in Daloa, one of the most important agricultural regions of Côte d'Ivoire. The experiments were carried out during the dry and rainy season and the experimental design was a Randomized Complete Block Design (RCBD) with three replications. The results showed the presence of wilt disease. The streaming test and bacterial culture on growth medium proved the bacterial origin of the wilt symptoms observed. The results of the staining reactions revealed short, straight, rod and Gram negative bacteria similar to R. solanacearum. The severity of the disease was found to be higher in the dry season than in the rainy season. Of 28 cultivars evaluated, 7 cultivars were resistant and did not show any diseased plants during the two study periods. These cultivars constitute interesting sources of resistance for a breeding program aimed at the development of new resistant cultivars adapted to the region of Daloa. Keywords: Bacterial wilt, Ralstonia solanacearum, resistance, tomato, Solanum lycopersicum, breeding program.