BIOLOGIC FORMS OF PUCCINIA GRAMINIS ON 
VARIETIES OF AVENA SPP.‘ 
By E. C. Stakman, Plant Pathologist, Department of Agriculture^ University of Minne^ 
sola, and Pathologist and Agent of the Office of Cereal Investigations, Bureau of Plant 
Industry, United States Department of Agriculture; M. N. L^vinE, Pathologist, Offiice 
of Cereal Investigations, Bureau of Plant Industry, United States Department of Agri¬ 
culture; and D. E. Bailey, Assistant in Plant Pathology, Department of Agriculture, 
University of Minnesota, and Agent, Offiice of Cereal Investigations, Bureau of Plant 
Industry, United States Department of Agriculture^ 
Puccinia graminis tritici Erikss. and Henn., which originally was con¬ 
sidered as a single biologic form, has been shown by Stakman and 
Piemeisel Levine and Stakman (5), Melchers and Parker (7), 
Stakman, Levine, and Leach (jo), and Stakman and Levine (p) actually 
to consist of many forms which differ in their parasitic action on certain 
varieties of Triticum spp. Hoemer (4) showed that there is a similar 
specialization of Puccinia coronata Cda. on varieties of Avena spp. and 
Mains and Jackson (6) found two biologic forms of P. triticina Erikss. on 
varieties of wheat. It seemed quite likely, therefore, that P, graminis 
avenae Erikss. and Henn. might also consist of several biologic forms. 
Experiments, therefore, were begun in the fall of 1918 to ascertain 
whether this was true. 
It is obvious that one of the most direct methods for ascertaining 
whether there are biologic forms of rust, with different parasitic capa¬ 
bilities on varieties of cereals, is to find forms of rust capable of infecting 
varieties ordinarily practically immune from described rust forms, or 
vice versa. As a result of preliminary studies on Puccinia graminis 
avenae it was found that Victory (both C. I. No. 1145 ^ and Minn. 514), 
Improved Ligowa (Minn. 281), Minota (Minn. 512), and many other 
varieties of oats were extremely susceptible to the rust strains® used, 
while White Tartar (White Russian) (Minn. 339 and two pure-line selec¬ 
tions made by the section of plant pathology at the Iowa Experiment 
Station and designated as Rust Nursery Row No. 101% and 102X), was 
quite resistant. The writers, therefore, began collecting uredinial 
material of P. graminis Pers. on oats from as many different localities as 
possible, in this and other countries. 
Since the fall of 1918, more than 100 collections of P, graminis on oats 
have been obtained from 21 States of the United States, from two Prov¬ 
inces in Canada, and from one State in Mexico. Seventy-six of the 
collections have iDeen cultured in the greenhouse of the section of plant 
pathology at University Farm, St. Paul, Minn. Many of these were 
used for inoculating seedlings of about 70 different varieties and selections 
^ Accepted for publication Feb. 20, 1923. Cooperative investigations between the OflBce of Cereal 
Investigations, Bureau of Plant Industry, U. S. D^artment of Agriculture and the Agricultural Experi¬ 
ment Station of the University of Minnesota. Published with the approval of the director, as Paper 355 
of the Journal Series. Minnesota Agricultural Experiment Station. 
* The writers are indebted for rust material to Prof. W. P. Fraser, pathologist in charge of Cereal Disease 
Investigations, Dominion Laboratory of Plant Pathology, in cooperation with the University of Saskatche¬ 
wan, Saskatoon, Sask, Canada; to Prof. Wallace Butler, of San Antonio, Tex.; to Mr. G. F. Puttick, of 
the Department of Agriculture of the Union of South Africa; and to Mr. Fred Griffee, assistant plant breeder, 
Department of Agriculture, University of Minnesota. They also are indebted to other Federal and State 
pathologists for collections of rust. 
Dr. H. K. Hayes, plant breeder, Department of Agriculture, University of Minnesota and collaborator 
of the Office of Cereal Investigations, Bureau of Plant Industry, U. S. Department of Agriculture, made 
valuable suggestions for which the authors wish to express their appreciation. 
® Reference is made by number (italic) to “Literature cited,” p. 1017-1018. 
< C. I.=Cereal investigations accession number. 
® The term “strain” is used only to designate a culture of rust from a single collection. 
Journal of Agricultural Research, 
Washington, D. C. 
afg 
Vol. XXIV, No. 12 
June 23, 1923 
Key No. ^315 
43326—23 - 7 
(1013) 
