K. Vasileva1*, N. Bogatzevska2

1Maritsa Vegetable Crops Research Institute, Agricultural Academy, 32 Brezovsko Shosse Str., 4003 Plovdiv, Bulgaria
2Institute of Soil Science, Agrotechnologies and Plant Protection “N. Pushkarov”, Agricultural Academy, 7 Shosse Bankya Str., 1331 Sofia, Bulgaria

(Manuscript received 15 December 2021; accepted for publication 10 May 2022)

Abstract. An economically important disease of the traditional vegetable pepper crop in Bulgaria is bacterial spot (Xanthomonas euvesicatoria and Xanthomonas vesicatoria). The resistance of pepper varietal types (Shipka, Pumpkin, Kapia) was determined by the species of causative agent of bacterial spot, pepper host specialization and structure of races. Shipka, Bulgarski ratund, Calabre and Ivaylovska kapia were classified in defined groups with a proven statistical difference depending on reaction to artificial inoculation with heterogeneous species X. euvesicatoria and X. vesicatoria. The cultivars from different types were medium sensitive to X. vesicatoria, independently of race P (P2), pathotype P3T2, P1T2 and the host from the strains was isolated. The races P3, P4 (P4T2p, t) to X. euvesicatoria were more virulent and aggressive than X. vesicatoria races P1 (P1T2t), P2, P3 (P3T2p). The genetic diversity between X. euvesicatoria and X. vesicatoria, their phylogenetic positions and composition of races, suggest the use of separate statistical analysis groups to determine the resistance of pepper cultivars.