a) 
enumerate them all) should be kept continuously before us: 
more nearly adequate salaries, a fund for retiring allowances, 
additional personnel, additional income for plants, books, publi- 
cation, laboratory equipment, and other items necessitated by 
the steady, normal growth of our work. 
Appended Papers 
Reports on Scientific Investigations for 1925, administrative 
reports of members of staff, the financial statement, and Ap- 
pendices 1-8 may be found on the following pages. 
Respectfully submitted, 
C. Stuart GAGER, 
Director. 
REPORTS ON RESEARCH FOR 1925 
Plant Pathology 
Disease Resistance. By GEorRGE M. REED 
Investigations with Oat Smuts.—In the last Annual Report 
mention was made of the discovery of specialized races of both the 
Loose Smut (Ustilago avenae) and Covered Smut (U. levis) of oats, 
which are characterized by their capacity for infecting particular 
oat varieties. Two races of loose smut were studied and while 
both of these were capable of attacking a wide range of varieties, 
yet they could be readily distinguished one from the other. 
The most significant difference between the two races was the 
failure of the one obtained from Wales to cause a severe infection 
of Avena nuda, a variety which has proved to be particularly 
susceptible to the other race from Missouri. Two races of 
covered smut were also studied. One of these has been grown 
for a number of years and is capable of attacking a large number 
of oat varieties belonging to the various species or sub-species of 
Avena. The second race was obtained from Wales and appeared 
to be confined almost entirely to certain varieties of Avena 
strigosa and to a strain of Avena brevis. These same varieties of 
A. strigosa were also susceptible to the other strain of covered 
smut. Avena brevis, however, has proved to be quite resistant, 
although a few infected plants have been observed. 
