RELATIVE SUSCEPTIBILITY OF SELECTIONS FROM A 
FULGHUM-SWEDISH SELECT CROSS TO THE SMUTS OF 
OATS 1 
By George M. Reed , 2 formerly Pathologist in charge of Smut Investigations , and 
T. R. Stanton, Agronomist in charge of Oat Investigations , Office of Cereal Investi¬ 
gations, Bureau of Plant Industry , United States Department of Agriculture 
INTRODUCTION 
Little is known concerning the reac¬ 
tion to the smuts of oats shown by 
selections from crosses between very 
Tesistant and very susceptible varieties. 
Definite information on the nature of 
infection, as well as on the mode of 
inheritance of smut resistance or smut 
susceptibility in such crosses, is es¬ 
sential for the breeding and develop¬ 
ment of smut immune varieties. The 
writers are cognizant of the fact that 
the data presented herein were obtained 
from studies of one cross only, but they 
seem conclusive enough to warrant 
publication. They are certainly an 
indication of the possibilities of the 
development, through hybridization, 
of strains of oats resistant to smut. 
It is evident that the production of 
economically desirable varieties of 
oats immune from, or highly resistant 
to, smut will be an important phase of 
varietal improvement in the future. 
REVIEW OF LITERATURE 
The studies of Biffen (If) 3 clearly 
demonstrated that resistance of wheat 
to Puccinia glumarum is inherited in 
typical Mendelian fashion. Biffen 
crossed the susceptible Red King with 
the resistant Rivet. The F x generation 
was susceptible. The F 2 progeny se¬ 
gregated into susceptible and resistant 
in an approximately three to one ratio. 
These results of Biffen recently have 
been confirmed by Armstrong (2 ). 
- Investigations of crosses between 
varieties of wheat susceptible or resist¬ 
ant to Puccinia graminis have been 
made by a number of workers. Hayes, 
Parker, and Kurtzweil (11) found that 
resistance was dominant in crosses 
between certain varieties of Triticum 
vulgare and T. dicoccum. On the other 
hand^ susceptibility was dominant in 
crosses of T. vulgare and T. durum. 
There also was a strong linkage be¬ 
tween rust resistance and the durum 
characters in the F 2 generation. Put- 
tick (18), Melchers and Parker (12), 
Aamodt ( 1 ), Garber (8), Harrington 
and Aamodt (9), and Hayes and 
Aamodt (10) have contributed addi¬ 
tional data on the general problem of 
the inheritance of resistance to Puccinia 
graminis , the organism causing stem 
rust. 
Gaines (6) has studied the inheritance 
of resistance to bunt or stinking smut 
(Tilletia tritid) of wheat. He crossed 
the resistant Turkey and the susceptible 
Hybrid No. 128, and also Turkey and 
Florence, both of which were resistant. 
In the first case, all degrees of resistance 
in the F 2 progeny were obtained. In 
the second cross, certain F 2 progenies 
proved to be more susceptible than 
either parent. 
Gaines, (7) in a second paper on the 
inheritance of resistance to bunt, 
states that this character in wheat is 
not a simple Mendelian unit character 
but, if Mendelian, is composed of mul¬ 
tiple factors. He further states that 
different wheat varieties possess dif¬ 
ferent kinds of resistance, and that 
linkage between resistance and mor¬ 
phological characters is not sufficient 
to hinder the selection of resistant 
strains of any type morphologically 
desirable. 
Wakabayashi (18) has studied the 
behavior of a cross between Red Rust¬ 
proof and Black Tartar oats in refer¬ 
ence to covered smut, Ustilago levis. 
The former variety is highly resistant 
while the latter is moderately suscepti¬ 
ble. The Fi and F 2 plants produced 
no smut. In the F 3 generation, how¬ 
ever, 12 families out of a total of 95 
were observed to contain a number of 
infected individuals. In no case, how¬ 
ever, was the number very large. 
1 Received for publication June 2, 1924; issued April, 1925, as Brooklyn Botanic Garden Contribution 
No. 39. Data for 1919 and 1920 obtained from investigations conducted cooperatively by the Office of Cereal 
Investigations, Bureau of Plant Industry, United States Department of Agriculture, and the Agricultural 
Experiment Station of the University of Idaho. Data for 1922 obtained from the Brooklyn Botanic 
2 Now curator of plant pathology at the Brooklyn Botanic Garden, Brooklyn, N. Y. 
3 Reference is made by number (italic) to “Literature cited,” p. 391. 
Journal of Agricultural Research, 
Washington, D. C. 
( 375 ) 
Vol. XXX, No. 4 
Feb. 15, 1925 
Key No. G-459 
