428 
Journal of Agricultural Research 
Vol. XXVII, No. 7 
tion, White Federation, and Bobs, of spring habit, the culms often show 
this character whether inoculated or not. Obviously, then, this can 
not be regarded as a trustworthy indication of the disease in these par¬ 
ticular cases. 
During the first year a detailed record was kept for each infected 
plant of the different varieties. Each plant was examined separately 
and the number of well-developed culms determined. In addition, the 
small undeveloped culms were noted. The nodes from which the roots 
developed, or the crown, were regarded as No. i, and the others were 
numbered successively from the base to the apex. The leaves from the 
first node usually were dead and dry at the time the plants were examined. 
This also frequently was true of the leaf at the second node, and some¬ 
times also of that at the third, depending upon the maturity of the plant. 
However, even in this semidry condition, it was possible to determine 
whether or not these lower leaves were infected. These plants had 
reached the heading stage, except in a few varieties where the severity 
of infection necessitated their removal from the greenhouse before that 
time. 
A summary of the data concerning total culm infection for nine 
varieties in the crop year 1919-20 is given in Table I. 
Table I. —Summarized results showing culm infection of wheat plants of different varieties 
infected with Urocystis tritici and grown in the greenhouse at Arlington Experiment 
Farm , Rosslyn, Va. f in igig-20 
Variety. 
Source or 
C. I. No. 
Number of plants— 
Per¬ 
centage 
of plants 
with all 
culms 
infected. 
Culms of partially infected 
plants. 
With one 
to all 
culms 
infected. 
With all 
culms 
infected. 
Total 
number. 
Number 
infected. 
i 
Per cent 
infected. 
Baart. 
1697 
16 
0 
0 
“3 
43 
38.1 
Bobs. 
4990 
40 
24 
60.0 
122 
93 
76.2 
Cowra No. 3. 
4119 
38 
30 
78.9 
52 
37 
7i.2 
Defiance. 
Calif. 
38 
5 
13.2 
268 
146 
54-5 
Fultz. 
3598 
18 
0 
0 
217 
114 
52.5 
Hard Federation. 
4733 
37 
29 
78.4 
51 
37 
72.s 
Harvest Queen. 
5957 
41 
28 
68.3 
142 
no 
77-5 
Do. 
Ill. 
3 1 
17 
54-8 
143 
116 
81.1 
Propo. 
1970 
18 
2 
u. 1 
96 
3 i 
32.3 
White Federation. 
498 1 
40 
29 
7 2 -5 
45 
29 
64.4 
In no variety were all culms infected on all infected plants, though in 
five varieties over 60 per cent of the plants had all their culms infected, 
while in two varieties no infected plant had all its culms infected. Of 
the partially infected plants—namely, those which had both sound and 
infected culms on the same plant—the percentage of culms infected 
ranged from 32.3 per cent to 81.1 per cent. In eight of these varieties 
over 50 per cent of the culms were infected. 
In general, every well-developed culm of an infected plant showed 
infection, the severity being indicated by the number, length, and size 
of the sori. Rarely a leaf showed no infection, though sori appeared on 
the leaves above and below. As a rule, however, any culm with the 
second or third leaf infected would show sori on all other leaves above. 
