44 
BULLETIN 1284, U. S. DEPARTMENT OF AGKICULTUEE 
was started. This continued until 100 seeds of each variety were 
germinated at each temperature range. The average growth of each 
variety in millimeters was thus obtained at the designated tempera- 
tures. It is believed these temperatures will closely approach the 
soil temperatures obtaining at the time when sorghums are generally 
planted. In the studies made at 19° to 21° C. no striking differences 
in growth between resistant and susceptible sorghums can be noted. 
Marked fluctuations, however, within the resistant group itself at 
these temperatures will be ' observed. Feterita, for example, germi- 
nated more rapidly than themilos. Table 13 shows that the susceptible 
sorghums as a group at all periods of growth grew about as rapidly 
as the resistant soi^ghums. Again it will be seen that feterita at these 
temperatures grew as rapidly as Red Amber and Black Amber sorgos. 
Table 
13. — Plumule length of various sorghums at 24-hour intervals when germi- 
nated at designated temperatures at Manhattan, Kans., in 1922 
Variety and serial number 
Average length of plumules (millimeters) 
Temperature 19° to 21° C. 
24 
hours 
48 
hours 
72 
hours 
hours 
Temperature 14° to 
16° C. 
72 
hours 
hours 
120 
hours 
Smut infec- 
tion 
(per cent) 
Aver- 
age 1 
Black Amber sorgo, S. P. I. No. 32384. 
Red Amber sorgo, S . P . I. No. 1 7548 . _ 
Gooseneck sorgo, Agrost . No . 2652 
Blackhull kafir, C.I. No. 207 
Sunrise kaflr, CI. No. 472* 
Dawn kafir, C . I. No. 340 
Progressive kafir, Kansas station 
Dwarf White milo, Kansas station 
Standard White milo, C. I. No. 352... 
Dwarf Yellow milo, Kansas station... 
Standard Yellow milo, Kansasstation. 
Feterita, C. I. No. 182 
Spur feterita, C.I. No. 623 
Darso, CI. No. 548 
Darso, C.I. No. 615 
Freed sorghum, C.I. No. 350 
Dwarf hegari, S.P.I. No. 34911 
Sudan corn, Kansas station ".. 
Husserita, Kansas station 
Shrock sorghum, C . I. No. 616 
0.04 







.03 


.17 
.07 

.05 
.21 
.05 
.04 
.48 
.73 
.35 
.31 
1.65 
1.30 
.29 
.83 
2.16 
1.22 
1.09 
1.65 
3.36 
2.17 
1.35 
1.70 
1.81 
1.60 
.25 
1.89 
2.25 
1.59 
1.32 
3.65 
2.65 
1.33 
1.82 
4.14 
2.31 
2.45 
3.37 
7.29 
5.00 
2.38 
4. 18 
3.93 
3.01 
.60 
4.06 
4.33 
3.27 
2.99 
6.34 
4.28 
3.33 
4.03 
5.78 
3.94 
4.45 
5.77 
2.21 
0.40 
.18 


.15 
.01 

.06 
.02 
.02 
.08 
.17 
.23 

.05 
.74 
.46 
.13 
.79 

0.94 
.79 
.07 
.22 
.59 
.29 

.29 
.50 
.13 
.30 
.97 
.79 
.04 
.27 
1.20 
1.26 
.78 
1.40 
1.52 
1.18 
.55 
.78 
1.05 
.96 
.01 
.82 
.93 
.48 
.87 
1.64 
1.37 
.19 
.62 
1.66 
1.85 
1.30 
1.80 
.33 
7.4 
10.5 
32.1 
7.4 
8.4 
13.6 
18.2 











7.7 
17.3 
2 16. 9 
2 12. 4 
3 32.1 
2 16.2 
2 22. 8 
5 14. 3 
10.1 

2 


2 


30 

30 

5.6 
11.2 
1 Average for two years except as noted. 
2 Average for six years. 
3 One y ear's data only. 
4 This lot proved to be not Sunrise kafir, but probably was Dawn kafir. 
'Average for three years. 
INFLUENCE OF EXTERNAL CONDITIONS ON KERNEL-SMUT 
INFECTION 
The sorghum smuts, like the smuts of other cereals, are dependent 
upon particular environmental conditions, more especially soil 
temperature and soil moisture. It is well recognized that the amount 
of smut varies greatly in different seasons, and its prevalence may be 
more or less correlated with the environing conditions at planting 
time. 
Kulkarni (63) has studied the influence of temperature on the 
germination of sorghum seed and also on the germination of the 
spores of SpJiacelotheca sorghi and S. omenta . He found that the 
