Effect of grafting on bacterial wilt disease, yield and quality of tomato (lycopersicon esculentum mill) In Bureti district, Kenya

Abstract

Bacterial wilt disease is a major setback to greenhouse tomato production in Bureti district, Kenya. The objective of this study was to evaluate the effects of grafting rootstock on disease tolerance, growth, yield and quality of the popular greenhouse grown ‘Anna F1’ tomato variety. Four rootstocks were screened, namely two African eggplants (wild Solanum aethiopicum and a cultivated variety, DB3), and common local varieties of wild tomato (Solanum lycopersici) and goat apple (Solanum aculeastrum). Experimental transplants were established inside greenhouse planted in the same season, using RCBD experimental layout. Treatments involved planting of ‘Anna F1’ grafted on each rootstock with, and without inoculation with bacterial wilt disease, with similar planting of un-grafted ‘Anna F1’ plants as control treatments. Data was collected fortnightly on bacterial wilt incidence, disease scores and plant height (cm). Total yields and associated attributes were observed at the reproductive stage, while fruit quality parameters (fruit diameter, brix and pH) were examined at 90 days after transplanting. The data were analyzed for variance (ANOVA) using GLM of SAS computer program. Mean comparison was done using Tukey’s HSD range test. Wild S. aethiopicum and DB3 rootstocks completely controlled bacterial wilt disease, showing no symptoms on grafts. Wilt incidences were also significantly reduced to 22.2% and 44.4% among wild tomato and goat apple grafts, respectively, compared to up to 100% wilt incidence among non grafted ‘Anna F1’ plants. Wild S. aethiopicum, DB3, and wild tomato rootstocks also consistently improved scion yield, under disease inoculation, achieving up to 76.3%, 51.2%, and 38.1% yield increases, respectively. Despite reduced fruit quality, their wilt tolerance and yield stabilizing effects supported their recommendation to growers challenged by severe (wild S. aethiopicum and DB3), and moderate (wild tomato) bacterial wilt disease infestation. The results of this study provide farmers with an environmentally safe method for controlling bacterial wilt disease