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.
