M. Koleva1*, I. Kiryakov2
1Department of Crop Science and Plant Protection, College Dobrich, Konstanin Preslavski University of Shumen, 9300 Dobrich, Bulgaria 2Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
Abstract. Pea (Pisum sativum L.) is a main grain leguminous crop in Bulgaria. Breeding resistant pea varieties is the most economically important method for disease control especially in pea bacterial blight, caused by Pseudomonas syringae pv. pisi. The investigation was carried out during 2013 – 2014 at Dobrudzha Agricultural Institute, General Toshevo. Forty-eight Pisum sp. accessions were used. Two strains of P. syringae pv. pisi (Bz4 and NCPPB 2585) were used. The plants were inoculated twice: at phenophase budding (petioles) and grain filling (pod) with bacterial suspension in concentration 1 х 108 CFU/ml using 1ml syringe. The reaction of the accessions was read 10 days after inoculation. A nine-degree scale was applied. According to the mean disease index (MDI) the accessions were divided into five groups: immune (I), resistant (R), middle resistant (MR), susceptible (S), very susceptible (VS). Twenty-five Pisum sp. accessions had resistant to moderately resistant reaction of leaves and pods to strain NCPPB and twelve accessions to strain Bz4, respectively. Eleven accessions (including P. sativum ssp. sativum, P. humile, P. elatius, P.s. var. hibernicum, P. abyssinicum, P. transcaucasicum, P. tibetanicum) had resistant reaction to leaves and pods to both strains. One of them is resistant to pea powdery mildew (Erysiphe pisi). Some accessions had different response of leaves and pods to both strains which confirms the position for different genetic control of resistance of leaves and pods. The results of our investigation showed that some Pisum sp. accessions could be used as a donor parent in a breeding program for bacterial or complex resistance on pea.