50 
REPORTS ON RESEARCH FOR 1934 
PLANT PATHOLOGY 
By GEORGE M. REED 
Studies on the Inheritance of Resistance of Oat Ilybrids to Loose 
and Covered Smuts 
Experiments with the Second Generation of Oat Ilybrids.—The 
second generation plants of four new hybrids were available for 
the study of inheritance of resistance to loose and covered smuts. 
One series of second generation plants of each hybrid was inocu- 
lated with the loose smut and another with the covered, and the 
percentage of infected plants determined. 
Canadian and Black Norway, the parental varieties of Hybrid 
83, are very susceptible to loose smut. Only 18 second generation 
plants were inoculated with it, 15 of which (83.3 per cent.) were 
infected. Apparently, the second generation plants are about as 
susceptible as the parental varieties. The variety Canadian is 
very susceptible to the covered smut, while Black Norway is 
resistant. There were 64 second generation plants inoculated 
with this smut and 8 (12.5 per cent.) were infected. Thus, the 
results indicate that resistance is dominant in inheritance. 
Hybrid 84 is a cross between Scottish Chief, a variety moder- 
ately susceptible to the loose smut and resistant to the covered, 
and Black Mesdag, a variety resistant to both smuts. There 
were 388 second generation plants of this hybrid inoculated with 
the loose smut and 70 (18 per cent.) were infected. In this 
hybrid also, resistance to the loose smut is dominant in inheri- 
tance. There were 182 second generation plants of this hybrid 
inoculated with the covered smut and 9 (4.9 per cent.) were 
infected. It is interesting to note that although both parents 
are very resistant to the covered smut, yet a few infected second 
generation plants appeared. 
Hybrid 85 1s a cross between Black Mesdag, resistant to both 
smuts, and Danish Island, a variety very susceptible to the loose 
smut and moderately susceptible to the covered smut. The 
were 118 second generation plants inoculated with the loose smut 
and 34 (28.8 per cent.) were infected. Again, resistance to the 
