78 
REPORTS ON RESEARCH FOR 1930 
Plant Pathology 
3y GEORGE M. ReEp 
Studies on the Inheritance of Resistance of Oat Hybrids to Loose 
and Covered Simut 
I*or several years investigations have been carried on in order 
to determine the mode of inheritance of smut resistance in oat 
hybrids. A large amount of data has been obtained with second 
generation plants of several different crosses and, in some cases, 
the experiments have been continued through the third and fourth 
generations. During the past year, additional data have been 
secured with a number of hybrids, representing different combina- 
tions of smut resistance. 
In our last report we recorded some data on hybrids between 
Ixarly Gothland and Monarch. The former is very susceptible to 
the loose smut, but resistant to the covered, while the Monarch 
variety shows exactly the reverse behavior with reference to the 
smuts. 50 second generation plants were inoculated with the 
loose smut, and g (18.0 per cent.) were infected. In another 
series, 85 second generation plants were inoculated with the covered 
smut, and 9 (10.5 per cent.) were infected. During the past year, 
several third generation progenies were grown, some individuals of 
which were inoculated with the loose smut and other individuals 
with the covered smut. The most significant results, perhaps, are 
that certain progenies were found to be entirely resistant to both 
loose and covered smut, while other progenies were more or less 
susceptible to one smut and resistant to the other. The results 
indicate that the factors determining resistance to the two smuts in 
these hybrids are independent of each other. The facts are par- 
ticularly significant in connection with the data already obtained in 
such crosses as Hull-less & Black Mesdag, in which the resistance 
to the two smuts appears to run entirely parallel. 
The fourth generation progenies of several of our earlier crosses 
were also grown, with a view to clearing up some of the problems 
involved. A large amount of data has been obtained and, in the 
main, the results are in harmony with those previously secured. 
Most of the studies during the past vear, however, were con- 
