THE INHERITANCE OF GROWTH HABIT AND RESIST¬ 
ANCE TO STEM RUST IN A CROSS BETWEEN TWO 
VARIETIES OF COMMON WHEAT ‘ 
By Oi^AE S. Aamodt 
Assistant Pathologist, Office of Cereal Investigations, Bureau of Plant Industry, United 
States Department of Agriculture, in cooperation with the University of Minnesota 
Department of Agriculture * 
INTRODUCTION 
There are three general methods by which the tremendous destruction 
of wheat by black stem rust may be reduced. These are the eradication 
of the common barberry {13),^ the growing of rust-resistant varieties 
(j, 10), and the use of improved methods of field culture (14). The losses 
have been especially severe in the hard red spring wheat area. No 
hard red spring wheat of high quality and yield, which is generally 
resistant to stem rust in the hard spring wheat belt, is now grown on 
a large acreage. Kota, apparently, is highly resistant to stem rust in 
those districts in which it has been grown, but on account of weak 
straw it is likely to lodge in the more humid sections. Therefore, the 
importance of developing other rust-resistant hard red spring wheats is 
, quite apparent. 
The production of varieties of wheat resistant to stem rust is a complex 
problem. Until recently it was supposed that only one form of stem rust 
caused the epidemics on wheat, although some of the early workers 
believed that the parasitic capabilities of the rust were easily modified 
{2). However, Stakman and Piemeisel (17), followed by others {8, 9, 15) 
have shown that Puccinia graminis tritici Erikss. and Henn. in reality 
consists of many biologic forms which differ in their pathogenicity for 
certain varieties of wheat. 
This discovery explains why the same variety of wheat may be resist¬ 
ant when grown in one locality and susceptible when grown in another, 
or why a variety may be resistant in the same locality in one year and 
susceptible in the next. It is obvious that if a wheat is to be resistant 
in the field it must be resistant to all of the biologic forms present in the 
locality in which it is to be grown. 
Both Kanred and Marquis are good milling and high yielding wheats. 
Kanred, however, is practically immune from several biologic forms of 
stem rust to which Marquis is susceptible. The purpose of tiiis paper is 
to present data regarding the mode of inheritance of growth habit (winter 
versus spring habit) and resistance to stem rust in a cross between 
Kanred and Marquis wheats. 
1 Accepted for publication Aug. 21, 1922. 
* This work on the development of rust-resistant varieties of wheat was under the direction of Dr. H. 
K. Hayes and Dr. E. C. Stakman. The cross was made in 1918 by Carl Kurtzweil and others. The seed 
of the first generation was furnished by Doctor Hayes. The biologic forms of rust were supplied by Doctor 
Stakman and Mr. M. N. Devine. 
* Reference is made by number (italic) to “Literature cited.” pp. 468-469. 
Journal of Agricultural Research, Vol. XXIV, No. 6 
Washington, D. C. May 12, 1923 
adu Key No. G-299 
39363—23 - 2 
( 4 S 7 ) 
