VIRULENCE DIFFERENCES BETWEEN TWO SPANISH ISOLATES OF SPHAEROTHECA FULIGINEA RACE 2 ON MELON

Powdery mildew caused by Sphaerotheca fuliginea is the most frequent melon disease in Spain.
Two of the physiological races described for the fungus have been detected in our country, race 1 which is spread all over the country and race 2 which was found during the early ’90s on protected crops in southeastern Spain.
In this work an isolate of S. fuliginea recently found on ‘PMR 45’ in Zaragoza was identified as race 2. As compared with a monosporic isolate of race 2 from Málaga, this isolate showed a different virulence pattern in artificial inoculations: the Zaragoza isolate did not infect the melon genotypes ‘Negro’, ‘BG 6011’ and ‘BG 6016’, while the Málaga isolate did.
These results indicate that the present classification of S. fuliginea into physiological races should be modified, since different isolates classified as belonging to race 2 are able to show different virulence/avirulence reactions.

VII Eucarpia Meeting on Cucurbit Genetics and Breeding

J.M. Alvarez, M.L. Gómez-Guillamón, N.A. Torés, I. Cánovas, E. Floris

Physiological races, powdery mildew, Sphaerotheca fuliginea

https://doi.org/10.17660/ActaHortic.2000.510.10