May, 1921. 



SCIENTIFIC AGRICULTURE 



213 



A Preliminary Note on the Occurrence of 



Biologic Forms of Wheat Stem Rust 



in Western Canada^ 



By MARGARET NEWTON.' 



Univrrsity of Saskatchewan, Saskatoon. 



Until 1916 only one biologic form of stem rust was 

 known to occur on wheat. During that year a form of 

 stem rust was collected by Stakman and Piemeisel in 

 the Palouse district of Washington and Idaho to which 

 certain varieties of wheat were almo.st immune, although 

 the same varieties of wheat in different localities could 

 only be explained by assuming that at least two bio- 

 logic forms of the rust fungus must be present, and 

 that cacli form could af^ct only certain wheats. 



An intensive study of the infection capabilities of 

 Puccinia c/raminis on wheat, including the isolation of as 

 many biologic forms as possible, and a. study of their 

 geographical distribution in the T'nited States, was im- 

 mediately begun by Stakman and Levine. The work 

 has continued and expanded until at the present time 

 practically all states have been surveyed, and numerous 

 strains have been isolated. 



The discovery of the occurrence of more than one 

 biologic form of stem rust was not only of scientific 

 interest but had a direct bearing on the breeding of 

 grain for rust resistance. It showed why "few varie- 

 ties seem to be universally rust resistant" (Freeman 

 and Johnson) and explained the diverse opinions of 

 workers in different localities as to the relative rust 

 resistance of certain wheat varieties. 



With these numerous forms of stem rust on wheat 

 present in the Tinited States, the question naturally 

 arose. Do biologic forms of stem rust occur in Canada? 

 Until the present investigation was undertaken, no 

 specific work had been done along these lines, although 

 observations made by Dr. W. P. Thompson of Saskat- 

 chewan University, in his breeding experiments, had 

 suggested very strongly that strains did exist. The 

 present work, therefore, was undertaken with the ob- 

 ject of discovering and isolating any biologic forms 

 of wheat stem rust which might occur in the great 

 grain-growing areas of western Canada. 



The work has been carried on for two years, and rust 

 from forty-three different regions of ilanitoba, Sask- 

 atchewan and Alberta has been tested. Great differ- 

 ences have been observed in the susceptibility of wheat 

 varieties to rust from various localities. Marquis, a 

 wheat quite susceptible to practically all forms of rust 

 in western Canada, is highly resistant to a form at 

 Indian Head. Two distinct biologic forms were found 

 at Saskatoon; one infected Emmer very heavily, while 

 the other scarcely infected it at all. In the same wav 



' Published with the permission of the Advisory 

 Council for Scientific and Industrial Research under 

 whose auspices this investigation was conducted. 



- Acknowledgement is made of the kind help and 

 direction received from Dr. E. C. Stakman and Mr. 

 M. N. Levine, Cereal Investigations, Bureau of Plant 

 Industry, at the Universit.v of Minnesota, and Professor 

 W. P. Fraser, Dominion Laboratory of Plant Pathology, 

 at the University of Saskatchewan. 



Kanred showed heavy, normal infection at Brandon, 

 Yorkton and Edmonton, and complete immunity at 

 Winnipeg and Vermilion. Some of the forms were 

 very virulent on many varieties while others were weak 

 and attacked only a few varieties succesfully. 



Eleven strains have so far been isolated in Canada. 

 It is interesting to note that they include no absolutely 

 new form, as all these strains have previously been 

 described in the United States by Stakman. In some 

 districts, such as Winnipeg and Indian Head, Uvo 

 strains were present. These differed from each other 

 only in their action on two varieties, but repeated in- 

 oculations gave these definite and consistent differ- 

 ences. 



A rather virulent strain was found to be quite widely 

 distributed. It was found in seventeen different local- 

 ities of Manitoba, Saskatchewan and Alberta. Should it 

 be discovered that this strain of rust is the prevailing 

 one in most of the wheat growing areas of Canada, the 

 problem of breeding for rust resistance would be con- 

 siderably simplified. 



As Stakman has pointed out "methods for breeding 

 for rust resistance must be changed fundamentally. 

 The breeder must know and work with those forms of 

 rust which occur in the region for which his new 

 variet.v is intended : and even then breeding must be 

 very largel.y a regional or even a local problem." 



The existence of separate and distinct strains of rust, 

 affecting certain varieties of wheat but non-virulent 

 for others, complicates the rust problem seriously. It 

 seems probable that the most effective method of con- 

 trolling the disease is by breeding resistant varieties, 

 but before this can be done effectively, much more 

 must be known of the number, characteristics and geo- 

 graphical distribution of biologic forms in Canada. 



RESULTS OF DOMINION ELECTION. 



On ^lay 2nd, the election ballots sent in to the Gen- 

 eral Secretary were opened in Ottawa by Mr, Ronald 

 Hooper, Honorary Secretary of the Proportional Re- 

 presentation Society. They were counted and assigned 

 to the various candidates, in the presence of the General 

 Secretary and the Honorary Secretary of the C.S.T.A. 

 There were 372 ballots received. The results were as 

 follows : 



President. L. S. Klinck, I'niversity of B. C, Van- 

 couver; First Vice-President. H. Barton, Macdonald 

 College, P.Q. ; Second Vice-President, John Bracken, 

 Agric^iltural College, Winnipeg, Man.; Honorary Se- 

 cretary, L. H. Newman, Ottawa, Ont. 



It will be noted from these results that, with the ex- 

 ception of the position of Second Vice-President, the 

 officers appointed last year have been re-elected. 



A few ballots were received after April 30th, and 

 were not, in consequence, available at the time the elec- 

 tion took place. Seventy-one per cent of the members 

 registered a vote. 



