title: Population structure ofStemphylium lycopersiciassociated with leaf spot of tomato in a single field.
abstract: Stemphylium lycopersiciis an important pathogen causing leaf spot of tomatoes worldwide. Although much information is available about the pathogen, little is known about dynamics ofS. lycopersiciin tomato fields. Seventy-nine symptomatic leaf samples were collected from two tomato cultivars grown in a farm (Miral and Inbred line). Fungal species associated with the disease were isolated on potato dextrose agar. Seventy-nine isolates were obtained and identified asS. lycopersicibased on sequence analysis of combined dataset of the internal transcribed spacer and glyceraldehyde-3-phosphate dehydrogenase regions. The 79 isolates were subjected to amplified fragment length polymorphism analysis using three primer combinations. TheStemphylium lycopersicipopulation from the two cultivars was found to have a very low level of genetic diversity (H = 0.0948). Cluster analysis showed intermixing of isolates from the two cultivars. In addition, analysis of molecular variance showed the presence of a very low level of genetic differentiation between populations obtained from the two cultivars (Fst= 0.0206). These findings indicate the presence of a high rate of gene flow between the two populations and may suggest that the two populations originated from the same inoculum source. The implications of these findings on the management ofStemphylium-induced leaf spot of tomatoes are discussed.
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Karima
authors.initials: K
authors.lastname: Al-Amri
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Al-Sadi
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Adel
authors.initials: A
authors.lastname: Al-Shihi
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Abbas
authors.initials: A
authors.lastname: Nasehi
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Issa
authors.initials: I
authors.lastname: Al-Mahmooli
authors.affiliation: Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, PO Box 34, 123, Al Khod, Muscat, Oman.
authors.forename: Mike L
authors.initials: ML
authors.lastname: Deadman
keywords: ITS; Phylogeny; Population structure; Solanum lycopersicum; gpd