Evaluation of tomato (Solanum lycopersicum L.) genotypes for bacterial wilt (Ralstonia solanacearum) resistance in Ghana

Abstract

Tomato (Solanum lycopersicum L.) is one of the most important vegetables which ranks second after potato in the world. Its productivity is extremely low due to the effect of pests and diseases. Bacterial wilt, caused by Ralstonia solanacearum is one of the most devastating and wide-spread bacterial diseases of tomato. The objective of the study was to identify tomato genotypes resistant to bacterial wilt disease that can be used for future improvement of the crop. The study collected and characterized 20 isolates from some major tomato growing areas in Ghana using both morphological and molecular tools to determine prevalent bacterial wilt strains, screenhouse and field evaluations coupled with marker assisted selection were used to identify resistant materials. In addition, broad sense heritability was estimated for bacterial wilt disease and other economic traits in tomato. From this present study, phylotype II was identified based on the molecular characterization. Four accessions H7996, LA 0442, LA 0443 and LA 0376 were identified to be resistant under both screenhouse and field conditions. For maker validation, six out of the twelve accessions possessed both Bwr-12 and Bwr-6 genes which confer resistance to BW disease. High broad-sense heritability was observed for both disease incidence, severity of BW disease, as well as other agronomic characters investigated. The four promising lines identified could be evaluated and subsequently released to farmers. In addition, findings from this study could be used to improve the tomato breeding programme in the country.