UNITED STATES DEPARTMENT OF AGRICULTURE 



I BULLETIN No. 1046 ^ 



Contribution from the Bureau of Plant Industry *%M 



_ WM. A. TAYLOR, Chief, in cooperation with the ^ , , 



S^S^'^^U Kansas Agricultural Experiment Station JfC^'^^^t^ 



Washington, D. C. ▼ May, 1922 



RUST RESISTANCE IN WINTER- WHEAT VARIETIES.^ 



By Leo E. Melchers, Plant Pathologist, and John H. Parker, in Charge of Crop 

 Improvement, Kansas Agricultural Experiment Station; Agents, Office of Cereal 

 Investigations. 



CONTENTS. 



Page. 



Scope of the investigation l 



Eeview of the literature 2 



Nursery experiments 4 



Greenhouse experiments 14 



•Comparison of nursery and greenhou se results 23 



Evidence of specifle rust resistance 24 



Agronomic value of Kanred wheat 26 



Summary 27 



Literature cited 30 



SCOPE OF THE INVESTIGATION. 



A project to determine the rust resistance of existing varieties of 

 winter wheats and to breed new varieties for rust resistance was 

 begun in 1911 at the Kansas Agricultural Experiment Station, in 

 cooperation with the Office of Cereal Investigations of the United 

 States Department of Agriculture. The first two years were devoted 

 to preparatory work, when no ififection of stem rust was produced. 

 The writers ^ took charge of the work in 1913, and the data given 

 herein are those obtained since that time. 



The investigation outlined in 1913 had two major purposes: (1) 

 To study the rust resistance of about 130 varieties and strains of 

 winter and spring wheats, particularly to the stem rust, Puccinia 

 graminis tritici Erikss. and Henn.,^ in the field and in the green- 

 house; and (2) to study the inheritance of rust resistance in wheat 

 and to produce hybrids adapted to commercial use. 



1 Paper No. 183 of the Department of Botany and Plant Pathology and No. 136 of the Department of 

 Agronomy, Kansas Agricultural Experiment Station. 



« The writers wish to acknowledge their indebtedness to Mr. Victor H. Florell and Mr. M. N, Levine, of 

 the Office of Cereal Investigations, who assisted in the greenhouse studies and in other phases of the 

 investigation. 



8 Puccinia graminis tritici, as used in this bulletin, has reference to those strains of stem rust used in 

 the experiments in 1915, 1916, and 1917. In 1915 a strain was used to which Kanred, P1066, and P1068 

 were only partially resistant, while in 1916 and 1917 strains were used to which these varieties were very 

 resistant. The strains used in 1916 and 1917 may have been one or more of the several strains which at 

 present are kno\\'ii not to cause normal infection of these varieties. 

 79251— 22— Bull. 1046 1 



