Summary
Twenty-one accessions of 3 wild Lactuca species which could be hybridised with L. sativa, the cultivated lettuce, were inoculated at different stages of plant development with 3 multivirulent isolates of Bremia lactucae. Nineteen sources of resistance to B. lactucae, not attributable to the previously recognised resistance factors 1–11 were identified. Two lines of L. serriola showed similar resistance patterns as lines carrying R11. The resistance of some accession was incomplete particularly at the seedling stage and this phenomenon may be race specific.
Tests on segregating F2 populations of crosses between 2 different L. serriola accessions and L. sativa cultivars showed that the resistance in one line (LSE/18) appears to be inherited as a single dominant gene, which is sometimes incomplete in expression and allelic to either Dm6 or R7. The segregation patterns for resistance in PI 281876 did not give readily interpretable ratios.
To assess the frequency of occurrence in B. lactucae populations of virulence factors to overcome this novel resistance, 11 of the novel sources of resistance were inoculated with numerous collections of the pathogen from the UK, Czechoslovakia and elsewhere and found to show a high level of resistance.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Crute, I. R. & A. A. Davis, 1977. Specificity of Bremia lactucae from Lactuca sativa. Trans. Br. mycol. Soc. 69: 405–410.
Crute, I. R. & C. H. Dickinson, 1976. The behaviour of Bremia lactuca on cultivars of Lactuca sativa and on other composites. Ann. appl. Biol. 82: 433–450.
Crute, I. R. & G. R. Dixon, 1978. Specific virulence in the British Bremia lactucae population. 3rd Int. Congr. Pl. Path., München, 16–23 August 1978.
Crute, I. R. & A. G. Johnson, 1976a. The genetic relationship between races of Bremia lactucae and cultivars of Lactuca sativa. Ann. appl. Biol. 83: 125–137.
Crute, I. R. & A. G. Johnson, 1976b. Breeding for resistance to lettuce downy mildew, Bremia lactucae. Ann. appl. Biol. 84: 287–290.
Crute, I. R. & J. M. Norwood, 1978. Incomplete specific resistance to Bremia lactucae in lettuce. Ann. appl. Biol. 89: 467–474.
Dixon, G. R. & I. R. Wright, 1978. Frequency and geographical distribution of specific virulence factors in Bremia lactucae populations in England from 1973–1975. Ann. appl. Biol. 88: 287–294.
Eenink, A. H., 1974. Resistance in Lactuca against Bremia lactucae. Euphytica 23: 411–416.
Ferakova, V., 1976. In: Flora Europaea, Vol. 4, pp. 328–331. Cambridge University Press.
Johnson, A. G., I. R. Crute & P. L. Gordon, 1977. The genetics of race specific resistance in lettuce (Lactuca sativa) to downy mildew (Bremia lactuca). Ann. appl. Biol. 86: 87–103.
Johnson, A. G., S. A. Laxton, I. R. Crute, P. L. Gordon & J. M. Norwood, 1978. Further work on the genetics of race specific resistance in lettuce (Lactuca sativa) to downy mildew (Bremia lactucae). Ann. appl. Biol. 89: 257–264.
Jones, B. L. & P. W. Leeper, 1971. Sources of immunity from race 5 and 6 of the lettuce downy mildew fungus (Bremia lactucae). Pl. Dis. Reptr 55: 794–796.
Lebeda, A., 1979a. Identification of races of Bremia lactucae in Czechoslovakia. Phytopath. Z. 94: 208–217.
Lebeda, A., 1979b. The occurrence of new races of Bremia lactucae in Czechoslovakia. Z. Pflanzenkrankh. Pflanzenschutz 86: 729–734.
Lebeda, A., 1980a. Establishment of virulence phenotypes in races of Bremia lactucae CS1, N1, N5 and N6. Phytopath. Z. 97: 289–294.
Lebeda, A., 1980b. The genetic structure of the host-pathogen system Lactuca sativa L. — Bremia lactucae Regel in Czechoslovakia. Proc. Eucarpia Meet. Leafy Vegetables, Littlehampton.
Lindquist, K., 1960. Cytogenetic studies in the serriola group of Lactuca. Hereditas 46: 73–147.
MacLean, D. J. & I. C. Tommerup, 1979. Histology and physiology of compatibility and incompatibility between lettuce and the downy mildew fungus Bremia lactucae Regel. Phys. Pl. Path. 14: 291–312.
Netzer, D., D. Globerson & J. Sacks, 1976. Lactuca saligna L. A new source of resistance to downy mildew (Bremia lactucae Regel). Hort. Sci. 11: 612–613.
Norwood, J. M. & I. R. Crute, 1979. Linkage between genes for resistance to downy mildew (Bremia lactucae) in lettuce. Ann. appl. Biol. 91: 127–135.
Prince, S. D. & R. M. Carter, 1977. Prickly lettuce (Lactuca serriola L.) in Britain. Watsonia 11: 331–338.
Robinson, R. A., 1976. Plant pathosystems. Advanced Series in Agricultural Sciences 3. Springer-Verlag Berlin/Heidelberg/New York 1976.
Robinson, R. A., 1980. New concepts in breeding for disease resistance. Ann. Rev. Phytopathol. 18: 189–210.
Thompson, R. C., T. W. Whitaker & W. F. Kosar, 1941. Interspecific genetic relationships in Lactuca. J. Agric. Res. 63: 91–107.
Wellving, A. & I. R. Crute, 1978. The virulence characteristics of Bremia lactucae populations present in Sweden from 1971–1976. Ann. appl. Biol. 89: 251–256.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Norwood, J.M., Crute, I.R. & Lebeda, A. The location and characteristics of novel sources of resistance to Bremia Lactucae Regel (downy mildew) in wild Lactuca L. Species. Euphytica 30, 659–668 (1981). https://doi.org/10.1007/BF00038794
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00038794