BULLETIN 1116, U. S. DEPARTMENT OF AGRICULTURE. 
degree of infection, represent the rate at which the seedlings were 
killed or injured by these fungi after the seed germinated. Hon- 
duras and Wataribune seed from California, as shown, germinated | 
much better than Louisiana seed of these varieties and were com- 
paratively free from fungi, especially of the types which cause injury. 
Honduras rice was selected for the hot-water treatments, as it is ~ 
a good commercial rice and one of the most susceptible to attack by 
these internal fungi. Table 3 shows the results of treatments on 
January 24 and February 2, 1920. The seed was sown in sterile 
agar plates, 20 seeds per plate. 
TaBLE 3.—Effect of hot-water treatment on the germination of Honduras rice seeds and - 
on fungi carried within the seeds. 

| 



Pre- | Pre- x 
sae s soaked | Soakedin | Germi-| Infec- B imates | soaked | Soakedin | Germi-| Infec- 
numer 0! jin tepid| hot water. | nation.) tion. : in tepid) hot water. | nation.| tion. 
experiment. water. experiment 


| water. 
Jan. 24, 1920:1 |} Hours.| °C. |Min.| P.ct. | P.ct. Jan. 24,1920:1| Hours.| °C. | Min.| P.ct. | P. ct. 
No. 10 83 No. 18 5 96 


Now de=22/* 164 55 ott - Notle.. 3: (2) 57 1 52 
INOSeios-2! 163 55 15 78 1 No. yee (2) 58 15 98 40 
Nor3e. 22 164} 54] 15 87 1 No. 20..... (2) (3) | (3) 96 62 
No. 4 164 | 56] 10 59 13 No. 21.23:5 64 | (3) | (3) 92 45 
No.5 163 56 15 47 3 Nog 22... 42 + (3) (3) 94 61 
ING 2622..-=.- 164 57 10 43 5 No: 2323 2 (3) (3) 94 67 
Nas 7e 335% 164 58 10 2 1 || Feb. 2, 1920: 4 
NG. S3..-<* a 55 15 93 17 No. ZA e235: 162 53 20 90 2 
NG. es ~ 56 10 91 24 Nos 25: . 72 163 53 15 91 4 
Nowt0:.-= 4 56 15 85 19 No. 26..... 162 33 10 86 13 
No. i tf 57 10 66 5 INORZ/a-. 162 54 20 7 3 
No. 12 4 o7 15 75 4 No. 28 163 54 15 93 1 
Nov13i:2= a 58 10 72 3 No. 29 16% 54 10 81 3 
No. 14 4 58 15 74 0 No. 30 162 55 15 71 3 
Wo;-15.20-5 2 | 56 15 89 20 INO. 31.2232 162 55 10 91 2 
Noot6h<—. 2 57 15 7 14 | INosceses: - 162 3 3 97 a2 
No. 17 2 | 58| 15 81 15 No. 33..... 2) | (a) | @) 96 | 47 
| | 
1 Soaked at 37° C.; germination in 10 days; infection in 13 days. 2 Not presoaked. *Not treated. 
4 Soaking started at 35° C., and the water was then allowed to come to room temperature; germination 
and infection in 8 days. 
Table 3 shows that the long presoaking period is more desirable. 
In each case the 15-minute treatments at 54° C. gave the best results, 
in both seed germination and fungus control. 
Further tests were made by soaking seed of Honduras rice from 
Louisiana at 54° C. for 15 minutes, after presoaking 16 hours and 50 
minutes in tepid water, and then sowing it along with untreated seed 
and seed of the same variety which was grown in California. Soil 
from a field where rice had never been grown was placed in large cans 
(16 by 16 inches and 15 inches deep), and the 50 and 100 seeds were 
sown in each can. The soil was in excellent condition, so the seed 
germinated readily, and none of the seedlings showed signs of blight. 
Table 4 gives the results of the germination of this seed. 

