RUST RESISTANCE IN WINTER-WHEAT VARIETIES. LZ 
size to accommodate about 72 plants. About half an inch of water 
was kept in the bottom of the chamber and a pan of water was sus- 
pended from the top. A cloth wick was placed over this pan and 
was allowed to hang down on two sides, as shown in Plate IX. 
This helped to keep the air saturated. A glass top allowed sufficient 
light to enter the moist chamber, so that the plants did not become 
etiolated during the incubation period. On warm days a stream of 
water was allowed to flow over the top, as illustrated in Plate X. 
This helped to maintain a cool temperature within the chamber. 
Cloths were hung over the outside walls to help distribute the water 
evenly. An overflow pipe in the pan at the bottom of the chamber 
carried away the surplus water. The inoculated plants were placed 
‘on inverted empty flowerpots, to avoid setting them in water. 
RESULTS OF THE GREENHOUSE EXPERIMENTS. 
The results obtained from greenhouse inoculations are shown in 
Table 3. Very heavy infection always was obtained on the checks 
and the susceptible varieties, but in the case of Kanred, P1066, and 
P1068 no uredinia appeared. Some of the spring-wheat varieties 
also showed only slight to moderate infection. The peduncles, 
glumes, and awns of all susceptible varieties were just as readily 
infected at heading time as were the seedlings. In the case of the 
three resistant varieties, if any portion of the head becomes infected 
it is the awn. No signs of infection, however, could be noticed on 
plants of the three resistant varieties with the exception of a few 
indefinite flecks on the culms. A plant of Improved Turkey was 
included with each set of varieties and on being inoculated was 
placed in the damp chamber and maintained under the same condi- 
tions. These checks always became heavily infected. It is evident 
that favorable conditions for infection were present, as uredinia were 
produced on plants of Khapli emmer (C. I. No. 4013), Kubanka 
durum (C. I. No. 2094), and other varieties of emmer and durum 
wheat which are known to be resistant to stem rust. 
The “type of infection,” is shown in the table by symbols (explained — 
below) indicating the relative resistance or susceptibility. The 
results of inoculations in the seedling and heading stages should be 
regarded as a corollary to the field results, however. It is hardly 
safe to draw final conclusions on the comparative resistance of va- 
rieties from experiments in the seedling stage alone, as the conditions 
under which the inoculations must be made are certain to vary and 
frequently may cause a different interpretation of the results. This 
is especially true where only a few seedlings are inoculated. A variety 
inoculated with a given strain of stem rust may show a somewhat 
different type of infection when inoculated at another time, even 
though the check which is run with every series may show a normal 
infection. 
