Evidence for a race-specific resistance factor in some lettuce (Lactuca sativaL.) cultivars previously considered to be universally susceptible toBremia lactucaeregel

✍ Scribed by I. R. Crute; A. Lebeda

• Book ID: 104691281
• Publisher: Springer
• Year: 1981
• Tongue: English
• Weight: 472 KB
• Volume: 60
• Category: Article
• ISSN: 0040-5752
• DOI: 10.1007/bf00264527

✦ Synopsis

Previously undetected race-specific resistance to Bremia lactucae (downy mildew) was located in many lettuce cultivars hitherto considered to be universally susceptible to this disease. This resistance factor(s) may also be widely distributed in other cultivars known to carry combinations of already recognised factors R1 to R11. Specific virulence to match this resistance is almost invariably present in pathogen collections. This situation may be either a relic of the evolutionary history of the B. lactucae - L. sativa asssociation or may reflect a rare mutation in B. lactucae for avirulence on all but a few specialised L. sativa genotypes.