Presenter: Debora Liabeuf
Advisor: Dr David Francis, Department of Horticulture and Crop Science
Proposal type: PhD proposal
Title of presentation: Development of processing tomato lines resistant to Xanthomonas gardneri: from screening to breeding
Abstract: Bacterial spot of tomato is caused by four species of Xanthomonas: X. euvesicatoria, X. vesicatoria, X. perforans and X. gardneri. The disease causes lesions on tomato leaves and black spot on fruits, leading to yield loss and nonmarketable tomatoes. The bacterial species X. gardneri has been recently implicated in outbreaks of bacterial spot on processing tomato fields in Brazil, Canada and the Mid-West United States. The damage caused by X. gardneri in 2010 in the Mid-West was estimated to be at least $7.8 million, spread over 2,000 ha of commercial processing tomato fields. As chemical solutions are currently not reliable to control bacterial spot, the development of varieties resistant to X. gardneri and to the other Xanthomonas species is of primary interest. The objectives of this project are (1) to identify source(s) of resistance to X. gardneri in cultivated tomato germplasm (Solanum lycopersicum) and in wild relatives (e.g., Solanum pimpinellifolium and S. lycopersicum var. cerasiformae); (2) to describe the genetic basis for resistance to X. gardneri discovered under objective 1, including the number of loci, gene action, and their location in the genome; (3) to create a strategy to combine resistance to the four species of Xanthomonas causing bacterial spot on tomato; (4) To develop a strategy to select lines combining high levels of resistance and traits suitable for market needs. The availability of processing tomato varieties containing resistance against bacterial spot will help growers to control the disease in their field, leading to a better yield and a better fruit quality.