Resistance of Bulgarian tomato varieties to the races of Xanthomonas vesicatoria

Abstract. Bacterial spot of tomato caused by Xanthomonas vesicatoria is an economically important disease that reduces the quality and the production yield. Races Т1, Т2 and Т3 have been differentiated in the natural population of X. vesicatoria. In this research 33 tomato varieties from the Bulgarian selection have been tested for their resistance towards X. vesicatoria. The varieties are characterized by different degrees of resistance. No immune and complex resistance has been found. The early and the mid-early indeterminate varieties are sensitive to the cause of bacterial spot. Variety IZK Alia of cherry type is moderately sensitive to races T1 and T3 but sensitive to race T2. Varieties Plovdivska karotina and BG Fantazia are resistant to race T1 and moderately sensitive to races T2 and T3. Varieties Nikolina F1 and Topaz are moderately sensitive to the three races. Bononiya and Venera are highly sensitive. In order to obtain genotypes with complex resistance to the races of X. vesicatoria further investigations should include: searching for new sources of resistance, conducting a selective breeding and increasing plant resistance sustainability.