80 
tibility to the loose smut, combined with high resistance to the 
covered. 
The progenies of 52 different crosses were grown. The gen- 
eral procedure in each case was to inoculate one set of second 
generation plants with the loose smut, and the other with the 
covered. A very large amount of valuable data bearing upon the 
general problem of the inheritance of the smut-resistant quality 
has been obtained. It is planned, during the coming season, to 
grow as many as possible of the third generation progenies of these 
various hybrids in order to determine quite fully the mode of in- 
heritance of the resistant quality. 
Some of our studies on the general problem of oat smut in- 
vestigations are in cooperation with Mr. T. R. Stanton, Senior 
Agronomist of the Office of Cereal Crops and Diseases at Wash- 
ington, D.C. Mr. Stanton has furnished some of the material for 
the study of the hybrids, and is also testing out, from the agronomic 
stan 
jae 
point, some of the lines which are promising on account of 
their smut resistance. 
Additional Physiologic Races of Oat Simatts 
The problem of the specialization of both the loose and covered 
smut of oats has continued to receive attention. A number of 
collections of both smuts have been received from Mr. T. R. 
Stanton, and these have been used to inoculate several varieties 
of oats. A number of new races have been isolated. These are 
particularly important from the standpoint of breeding oats for 
smut resistance. 
Influence of Environal Conditions on Oat Simaut Infection 
Some experiments have been carried out with reference to ex- 
ternal factors influencing oat smut infection. Usually, with a 
susceptible variety, by the proper combination of conditions, we 
are able to secure the infection of all the inoculated plants. The 
most favorable combination of factors 
—_— 
las previously been worked 
out. During the past year, however, experiments were conducted 
to determine whether the growth of the host plant would influence 
the subsequent development of the parasite. All the plants were 
subjected to the same conditions during the seedling stage in order 
