Plant Genome III Conference Plant Genome III Conference
Apple scab is one of the most important fungal diseases of apple. To control this disease, 5 to 12 fungicide sprays may be needed. At least 5 dominant genetic sources of resistance to scab are available, but molecular markers have not been developed for each source of resistance. About 500 random sequence 10-mer primers were screened against two DNA bulks from resistant and susceptible progeny in Empire' x 'Nova Easygro' to identify molecular markers linked to the resistance gene(s). Four markers generated from primer B398, B533, OT02 and OPA15 were found to be linked to a major gene derived from 'Nova Easygro'. Two of the closely linked markers produced from B398 and OPA 15 were sequenced to design specific primers. Different progeny in the breeding program were tested with the specific primers and successful amplifications were obtained. These markers will also be used as starting points towards cloning the major gene by employing map-based cloning techniques. The nature of the resistance gene from 'Nova Easygro' and its relation to other scab resistance genes will be discussed.