Stabilizing Selection for Pathogenicity in Cereal Rust Fungi

  • Mohammad Aslam
  • L. E. Browder
Part of the Basic Life Sciences book series (BLSC, volume 8)


Experimental evidence indicates that stabilizing selection for pathogenicity is operative in cereal rust fungi. Similar evidence for other plant parasitic fungi is also presented. Studies on Puccinia recondita showed that the number of loci for high pathogenicity in a parasite culture and its relative ability to increase in a mixed population are inversely related. Parasite cultures with fewer number of loci for high pathogenicity exhibited greater longevity in vitro, higher infectivity, shorter incubation period, and greater adaptability to varying temperature and light conditions. Based on empirical evidence it is concluded that in a mixed population, in a compatible host:parasite system, low pathogenicity is selected for and high pathogenicity against. In natural populations equilibrium is soon established between low and high pathogenicity provided that the host population is not changed and compatibility is maintained in the host:parasite system. It is proposed that high pathogenicity is the result of a deletion of the locus for low pathogenicity. Possibly, then, a chromosomal segment carrying gene(s) for vital metabolic activity is also removed, thus making the parasite culture unable to compete with other members of the population which do not carry such deletion.


Leaf Rust Parasite Population High Pathogenicity Parasite Culture Common Host 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Aslam, M. (1972). Aggressiveness in Puccinia recondita Rob. ex Desm. F. sp. tritici. I. Concepts and terminology. II. Predominance of one culture over another in composites. III. Components of aggressiveness. Ph.D. dissertation, Kansas State Univ., Manhattan, Ks., 90 pp.Google Scholar
  2. Aslam, M. (1975). Pathogenic specialization in Puccinia recondita f. sp. tritici in NWFP. Agri Pakistan 26(2): 171–175.Google Scholar
  3. Browder, L. E. (1965). Aggressiveness in Puccinia graminis var. tritici. Ph.D. dissertation. Kansas State Univ., Manhattan, Ks., 111 pp.Google Scholar
  4. Brown, J. F. and Sharp, E. L. (1970). The relative survival ability of pathogenic types of Puccinia striiformis in mixtures. Phytopa Google Scholar
  5. Bugbee, W. M. (1965). Studies on the aggressiveness of Race 15B and Race 56 and progenies from crosses of these races of Puccinia graminis var. tritici. Ph.D. dissertation, Univ. of Minnesota, St. Paul. 70 pp.Google Scholar
  6. Flor, H. H. (1953). Epidemiology of flax rust in the North Central States. Phytopathology 43: 624–628.Google Scholar
  7. Flor, H. H. (1955). Host-parasite interaction in flax rust-its genetic and other implications. Phytopathology 45: 680–685.Google Scholar
  8. Flor, H. H. (1959). Genetic controls of host-parasite interactions in rust diseases. In Plant Pathology-problems and Progress 1908–1958 ( Holton et al., eds.) pp. 137–144. Univ. of Wisconsin Press, Madison.Google Scholar
  9. Flor, H. H. (1960). The inheritance of X-ray induced mutations to virulence in uredospore culture of race 1 of Melampsora lint Phytopathology 50: 603–605.Google Scholar
  10. Green, G. J. (1971). Physiologic races of wheat stem rust in Canada from 1919 to 1969. Can. J. Bot. 49: 1575–1588.CrossRefGoogle Scholar
  11. Hussain, S. M. (1956). Studies on competitive ability in certain races of wheat leaf rust. M. S. thesis, Oklahoma State Univ., Stillwater, Ok., 33 pp.Google Scholar
  12. Jackson, H. S. (1931). Present evolutionary tendencies and the origin of life cycles in the Uredinales. Mem. Torr. Bot. Club 18: 1–108.Google Scholar
  13. Kak, D., Joshi, L. M., Prasada, R. and Vasudeva, R. S. (1963). Survival of races of Puccinia graminis tritici (Pers.) Erikss. and J. Heim. Indian Phytopathol. 16: 117–126.Google Scholar
  14. Katsuya, K. and Green, G. J. (1966). Reproductive potentials of race 15B and 56 of wheat stem rust. Can. J. Bot. 45: 1077–1091.CrossRefGoogle Scholar
  15. Leonard, K. J. (1969). Selection in heterozygous populations of Puccinia graminis f. sp. avenae. Phytopathology 59: 1851–1857.Google Scholar
  16. Loegering, W. Q. (1951). Survival of races of wheat stem rust in mixtures. Phytopathology 41: 56–65.Google Scholar
  17. Ogle, H. J. and Brown, J. F. (1970). Relative ability of two strains of Puccinia graminis tritici to survive when mixed. Ann. Appl. Biol. 66: 273–279.CrossRefGoogle Scholar
  18. Person, C. O. (1959). Gene-for-gene relationship in host:parasite systems. Can. J. Bot. 37: 1101–1130.CrossRefGoogle Scholar
  19. Samborski, D. J. (1963). A mutation in Puccinia recondita Rob, ex Desm. f. sp. tritici to virulence on Transfer, Chinese Spring X Aegilops umbellulata Zhuk. Can. J. Bot. 41: 475–479.CrossRefGoogle Scholar
  20. Samborski, D. J. (1971). Leaf rust of wheat in Canada in 1970. Can. Plant Dis. Surv. 51: 17–19.Google Scholar
  21. Schwinghammer, E. A. (1959). The relation between radiation dose and frequency of mutations for pathogenicity in Melampsora lini. Phytopathology 49: 260–296.Google Scholar
  22. Van der Plank, J. E. (1963). Plant disease Epidemics and Control, 349 pp. Academic Press, New York.Google Scholar
  23. Van der Plank, J. E. (1968). Disease resistance in Plants, 206 pp. Academic Press, New York.Google Scholar
  24. Watson, I. A. (1942). The development of physiological races of Puccinia graminis tritici singly and in association with others. Proc. Linn. Soc. N.S.W. 67: 294–312.Google Scholar
  25. Watson, J. A. (1958). The present status of breeding disease resistant wheats in Australia. N. S.W. Dept. Agri. Gaz. 69: 630–660.Google Scholar
  26. Watson, I. A. and Luig, N. H. (1961). Leaf rust on wheat in Australia: A systematic scheme for the classification of strains. Proc. Linn. Soc. N.S.W. 86: 241–250.Google Scholar
  27. Williams, N. D., Gough, F. J., and Rondon, M. R. (1966). Interaction of pathogenicity genes in Puccinia graminis f. sp. tritici and reaction genes in Triticum aestivum ssp. vulgare “Marquis” and “Reliance.” Crop Set 6: 245–248.Google Scholar

Copyright information

© Plenum Press, New York 1977

Authors and Affiliations

  • Mohammad Aslam
    • 1
  • L. E. Browder
    • 2
  1. 1.Agricultural Research InstituteTarnab, PeshawarPakistan
  2. 2.Department of Plant PathologyKansas State UniversityManhattanUSA

Personalised recommendations