Tomato Resistance To Fusarium Wilt Disease: Effect Of Grafting Combination And Molecular Characterisation Of Fusarium Isolates

Abstract

Recently, tomato cultivation in the Berekum West District of Ghana faced a severe yield loss due to Fusarium wilt disease. In this study, a survey was conducted to assess farmers’ knowledge on prevalence, spread, control, economic importance, and the use of grafted tomato to manage tomato wilt disease. Six communities were selected to determine the incidence and severity of the disease and identify the causal organism of the wilt using molecular markers. Based on molecular identification using Internal Transcribed Spacer (ITS) region sequencing did not only identify Fusarium oxysporum isolate but in addition, Fusarium equiseti isolate was identified as the causal organism of the wilt disease in Berekum West District. Out of several Solanum plants screen for resistance against Fusarium wilt, the best two, Solanum macrocarpon and Solanum torvum were selected as rootstock for grafting onto Solanum lycopersicum (Petomech). Plant growth, yield improvement and disease management of both grafted plants, non-grafted plant were evaluated under artificial inoculation condition (4.4 x 10^6 spores suspension) in a pot experiment and under a naturally infected open field condition at Berekum. There was significant interactive effective between the rootstocks and Fusarium inoculum, where grafting was effective in reducing the disease severity and incidence on the field and in the pot experiment. There was also a significant interactive effect on the growth, photosynthetic activity and yield but the fruit quality traits of either grafted and non-grafted plants showed similar or no significant differences. For the pot experiment, Petomech grafted onto Solanum macrocarpon produced significantly higher yield 453.1 g per plant compared to Petomech grafted onto Solanum torvum (350.3 g) and non-grafted plant (205 g). However, under the open field experiment (naturally infected field), Petomech grafted onto S. torvum produced the highest fruit per plant (158 g), Petomech grafted onto S. macrocarpon (148.7 g) and non-grafted petomech produced 51.4 g per plant. Overall, grafting was effective tool used to improve the yield and growth of tomato plants in a Fusarium infected field.