WILD LYCOPERSICON SPECIES AS SOURCES FOR RESISTANCE TO POWDERY MILDEW (OIDIUM LYCOPERSICUM): MAPPING OF THE RESISTANCE GENE OL-1 ON CHROMOSOME 6 OF L. HIRSUTUM

P. Lindhout, H. Beek, G. Pet
Since the late 1980's powdery mildew, designated Oidium lycopersicum, is endemic in the tomato crop in Western Europe. All commercial cultivars are susceptible. One hundred and twenty seven accessions, representing eight wild Lycopersicon species, were screened for resistance to O. lycopersicum. A large variation in resistance was found between species. High levels of resistance were observed in four accessions of L. hirsutum, in one of L. parviflorum and in one of L. peruvianum. These six accessions are compatible with the cultivated tomato and offer good perspectives for resistance breeding programmes.

The inheritance of resistance to O. lycopersicum from L. hirsutum G1. 1560 and from L. parviflorum CPR0731089 was investigated by disease tests in segregating interspecific F2 and BC1 populations. One dominant gene, designated O1-1 was found to control resistance from L. hirsutum and one recessive gene, designated o1-2 controlled the resistance in L. parviflorum.

To map O1-1, bulks of resistant and susceptible plants from the F2 population of L. esculentum x L. hirsutum G1.1560 were analyzed for Random Amplified Polymorphic DNA (RAPD). One RAPD was amplified in the susceptible bulk and not in the resistant bulk. This RAPD was mapped on chromosome 6 by linkage analysis with RFLP markers in an F2 (L. esculentum x L. pennellii). By RFLP analysis of the segregating F2 population L. esculentum x L. hirsutum the O1-1 locus was mapped near the Aps-1 region on chromosome 6.

Lindhout, P., Beek, H. and Pet, G. (1994). WILD LYCOPERSICON SPECIES AS SOURCES FOR RESISTANCE TO POWDERY MILDEW (OIDIUM LYCOPERSICUM): MAPPING OF THE RESISTANCE GENE OL-1 ON CHROMOSOME 6 OF L. HIRSUTUM. Acta Hortic. 376, 387-394
DOI: 10.17660/ActaHortic.1994.376.53
https://doi.org/10.17660/ActaHortic.1994.376.53
tomato, genetics, disease resistance breeding

Acta Horticulturae