Inheritance of resistance to XcvT and XcvPT of Xanthomonas campestris pv. vesicatoria
Sotirova, V., Bogatsevska, N.2 and Vulkova, Z1.1
1Institute of Genetics, Sofia 1113, BAS 2Institute of Plant Protection, Kostinbrad 2230
Bacterial spot caused by Xanthomonas campestris pv. vesicatoria is a serious disease on tomatoes. Three
pathotypes of the pathogen have been identified (Ritch, Dithapongpitch, 1991). Two pathotypes of Xcv- tomato
(XcvT) and pepper-tomato (XcvPT) have been established in Bulgaria (Bogatsevska and Sotirova, 1992). In
recent years, resistance to XcvT and XcvPT has been discovered in tomato lines obtained by complex
interspecific hybridization (Sotirova and Bogatsevska, 1995). The hybrid population derived from resistant line
LCH 168 and susceptible cultivar Ace were used in the investigation. The plants 5-6 true leaves were inoculated
with the suspension from both XcvT and XcvPT pathotypes by using the vacuum infiltration method (Bogatsevska,
1988). Disease expression was graded by using 5-grade scale described by Sotirova and Beleva (1975). The
disease severity of the plants in F, population from the Ace x LCH 168 cross was close to the midparent value
(data not shown) but was always skewed towards the resistant plants. The F2 population segregated in 3 resistant:
1 susceptible plant with a probability value (P) of 0.20-0.50. The BC1P1 segregated in 1 resistant : 1 susceptible
plant (Table 1). The data suppose that the resistance to XcvT and XcvPT pathotypes of Xanthomonas campestris
pv. vesicatoria was inherited with incomplete dominance and controlled by a single gene.
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