54 
races of loose and covered smuts. Studies with these hybrids 
have also been continued over a period of several years, and are 
now being prepared for early publication. 
The very extensive results obtained with the hybrids between 
Black Mesdag and Hull-less, Silvermine, and Early Champion, 
were published during the past year. The accumulated data 
extended over the second, third, fourth, and fifth generations. 
One of the most interesting features of the results with these 
hybrids was the similarity in their behavior to both loose and 
covered smuts. 
The results with another series of hybrids were published in co- 
operation with T. R. Stanton, Senior Agronomist, Division of 
Cereal Crops and Diseases, Bureau of Plant Industry, and F. A. 
Coffman, Associate Agronomist, Division of Cereal Crops and 
Diseases, Bureau of Plant Industry, Washington, D. C. These 
hybrids involved various combinations in the resistance of the 
parental varieties. 
Physiologic Races of Oat Smuts 
During the past year, particular attention was paid to collec- 
tions of smuts on varieties belonging to the red group of oats. 
Five different collections of covered smut on Fulghum, nine 
collections of loose smut on Fulghum, and four collections of loose 
smut on Red Rustproof, were grown on an extensive series of oat 
varieties in order to determine the degree of specialization of these 
smuts. It is definitely established that the Fulghum race of loose 
smut is very distinct from the Red Rustproof race, and that both 
races can be readily separated from many other highly specialized 
races of loose smut. 
The covered smut on Fulghum is particularly interesting be- 
cause of its ability to attack Black Mesdag, a variety of oats 
which is very resistant to collections of both loose and covered 
smuts. 
The data obtained have been combined with other data secured 
in past years and, in cooperation with T. R. Stanton, Senior 
Agronomist, Division of Cereal Crops and Diseases, Bureau of 
Plant Industry, Washington, D. C., the results are now being 
prepared for publication, 
