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Inheritance of Resistance to Blight (Phytophthora infestans) in Potatoes: Strain C and its Relationships*

  • William Black (a1)


The common strain A of the blight fungus (Phytophthora infestans) and two new strains, B and C, have been employed in testing potato varieties and seedling progenies, bred from the wild species S. demissum, for resistance to the disease. The reactions of seedlings to infection with strain C are compared with those of strains A and B. The C strain is shown to be more virulent than A, since it attacks some A resistant as well as all A susceptible plants. Likewise the B strain is more virulent than A. The difference between the pathogenicity of strains B and C, however, is not one of degree of virulence; one plant may be B resistant-C susceptible, while another may be B susceptible-C resistant. This difference is essentially of a qualitative nature. Resistance to these strains, which is manifested by the hypersensitive condition of the plant's cells, is produced in the presence of three major independent genes, Re, Rb and Rbc, which confer resistance to strains A and C, A and B, and A, B and C respectively. Segregations in each case are similar in type, and are characterised by an excess of recessive individuals.



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This paper was assisted by a grant from the Carnegie Trust for the Universities of Scotland.



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Black, W., 1943. “Inheritance of Resistance to Two Strains of Blight (Phytophthora infestans de Bary) in Potatoes”, Trans. Roy. Soc. Edin., LXI, 137–I47
Black, W., 1945. “Inheritance of Resistance to Blight (Phytophthora infestans) in Potatoes: Unbalanced Segregations”, Proc. Roy. Soc. Edin., B, LXII, 171181.
Black, W., 1947. “Blight in Relation to Potato Breeding”, Ann. Appl. Biol., xxxiv, 631633.
Black, W., 1949. “Inheritance of Resistance to Blight (Phytophthora infestans) in Potatoes: Comparison of A and B Strains”, Proc. Roy. Soc. Edin., B, LXIII, 290301.
Black, W., And Haigh, J. C, 1947. “Strains of Potato Blight in Scotland”, Scottish Agriculture, xxvn, 4950.
Bruyn, H. L. G. D E, 1947. “Het Rassenprobleem Bij Phytophthora infestans”, Vakbl. Biol., xxvn, 147152.
Keay, M. A., 1949. “Report on the Material of Phytophthora infestans (Mont.) de Bary”, collected by the National Agricultural Advisory Service, in 1948, for the Commonwealth Potato Station, Cambridge.
Müller, K. O., 1941. “Physiologisch-genetisch Untersuchungen zur Analyse der Phytophthora-Resistenz der Kartoffel”, Proc. Vllth Int. Genet. Congr., Edinburgh, 1939, pp. 222–223.
Müller, K. O., And behr, L., 1949. “Mechanism’ of Phytophthora Resistance of Potatoes”, Nature, London, CLXIII, 498499.
Müller, K. O., And Börger, H., 1941. “Experimented Untersuchungen über die Phytophthora-Resistenz der Kartoffelzugleich ein Beitrag zum Problem der ‘erworbenen Resistenz’ im Pflanzenreich”, Arb. Biol. Reichsanst. Land.-u.-Forstw., Berlin, XXIII, 189231.
Reddick, D., And Mills, W., 1938. “Building up Virulence in Phytophthora infestans”, Amer. Pot. Journ., xv, 2934.

Inheritance of Resistance to Blight (Phytophthora infestans) in Potatoes: Strain C and its Relationships*

  • William Black (a1)


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