Localization of genes for bacterial canker resistance in Lycopersicon peruvianum using RFLPs

A backcross population of the L. peruvianum accession LA 2157, which is resistant to bacterial canker caused by Clavibacter michiganensis ssp. michiganensis, with the susceptible L. peruvianum accession LA 2172 was evaluated for the segregation of C. michiganenis resistance and of RFLP markers in order to map the loci involved in this resistance. The development of symptoms of the disease was scored using an ordinal scale. The mapping of the disease resistance was hampered by distorted segregation ratios of a large number of markers and unexpected quantitative inheritance of the resistance. By means of the Kruskal-Wallis rank-sum test, five regions on chromosomes 1, 6, 7, 8 and 10 were identified that may be involved in C. michiganensis resistance.