STUDY OF THE 3-GENOME HYBRID LYCOPERSICON-ESCULENTUM MILL - L-CHILENSE DUN - LYCOPERSICON-PERUVIANUM VAR HUMIFUSUM MILL AND ITS USE AS A SOURCE FOR RESISTANCE

L. peruvianum var 'humifusum' is reproductively the most isolated of the species of the genus Lycopersicon. It can be crossed with the cultivated tomato using L. chilense as an intermediary. After a series of backcrosses of the three-genome hybrid F1 (L. esculentum x L. chilense) x L. peruvianum var 'humifusum' with L. esculentum, accompanied by selection for resistance to some economically important diseases, several lines were established. One of these lines, Cm 180, which showed resistance to Clavibacter michiganensis subsp. michiganensis, was subjected to genetic analysis. This resistance was found to be controlled by a single dominant gene (Cm) that was not allelic to the gene originating from L. hirsutum f. glabratum. This Cm gene was genetically mapped on chromosome 4. The germ plasm of L. peruvianum var 'humifusum' in combination with L. chilense was transferred into L. esculentum. Different breeding lines possessing resistance to various diseases and pests could be developed from this material.