Inheritance and sources of resistance to bacterial speck of tomato caused by Pseudomonas syringae pv. tomato

Inheritance of resistance to bacterial speck of tomato was determined by analysing F₁ F₂ and backcross progenies of crosses involving a susceptible (VF‐198) and a resistant cultivar (Rehovot‐13). The results fit the hypothesis that resistance is controlled by a single dominant gene in interaction with minor genes. Cultivar susceptibility to Pseudomonas syringae pv. tomato was tested under greenhouse conditions under high inoculum pressure using infested tomato seeds together with infested soils and spray‐inoculated wounded plants. Of 21 species, cultivars and lines, Rehovot‐13, Ontario 7710 and Lycopersiconpimpinellifolium P.I. 126927 were found to be resistant to the pathogen. VF‐198 and Tropic‐VF were the most susceptible. Extra Marmande, Saladette, Acc.339944–3 and the wild type Lycopersicon esculentum var. cerasiforme were moderately resistant.