SEEDLING BLIGHT AND STACK-BUEN OF RICE. 



Table 4. — Germination of Honduras rice seeds from Louisiana treated in water at 

 54° C. for 15 minutes, after presoaking 16 hours and 50 minutes, as compared with 

 untreated Louisiana and California seeds of the same variety. 







Louisiana seeds. 





California seeds. 



Date sown and number of 

 experiment. 



Treated. 



Untreated. 



Untreated. 





Number. 



Germina- 

 tion. 



Number. 



Germina- 

 tion. 



Number. 



Germina- 

 tion. 



May 3, 1920: 



No. 1 



Per cent. 



250 

 250 

 250 

 2.50 

 250 

 250 

 250 

 250 



200 

 200 

 200 

 500 

 500 



Per cent. 

 52.40 

 46.00 

 68.40 

 64.80 

 65.60 

 70.80 

 72.40 

 62.00 



64.00 

 85.50 

 65.00 

 63.00 

 68.60 



250 

 250 

 250 

 250 

 250 

 250 

 250 

 250 



400 

 400 

 400 



Per cent. 

 55.20 



No. 2 





70.80 



No. 3 





78.40 



No. 4 



1 



64.40 



No.5 



j 



75.20 



No. 6 



i 



86.40 



No. 7 





84.40 



No. 8 





78.80 



May 21, 1921: 



No. 13 



400 

 400 

 400 

 500 

 500 



70.50 

 75.00 

 65. 50 

 53.60 

 70.60 



72.75 



No. 14 



74.00 



No. 15 



63.50 



No. 16 





No. 17 







No. 18 



1,000 



500 



1,000 



66.10 



No. 19 



500 



63.50 







73.80 



No. 20 







67.00 









1 





Total 



2,700 





3,600 





5,700 





Average.. 



65.96 



64.80 



70.61 













Nishikado and Miyake ^ conducted extensive hot-water treatment 

 experiments on the Minaribo variety of rice in Japan. Unfortunately, 

 the results of this work were not available to the writer until after 

 his work on rice was discontinued. These Japanese investigators 

 found that the temperature of the hot water which could be used 

 effectively on rice depended to a large extent on the length of the 

 presoak. They reported no seed injury by treating unsoaked rice 

 for 15 minutes at 55° C. The writer found no injury to Honduras 

 rice when it was treated at 58° C. for 15 minutes without presoak 

 (Tables). 



The Japanese writers mentioned no injury to seed presoaked for 

 different periods up to 16 hours and treated for 5 and 10 minutes in 

 water at 54° C, but a 15-minute soak in hot water caused a slight 

 decrease in germination. Where they presoaked the seed 24 and 48 

 hours, respectively, a 10-minute soak in hot water at 54° C. caused 

 some injury. Their results also show that seed treated with hot water 

 germinated better than their untreated controls. The writer found 

 that a soaking in water at 54° C. for 15 minutes after presoaking for 

 16 hours killed the internal fungi' and came nearest to giving as good 

 germination as the untreated controls. In practically every case, 

 however, the germmation was slightly lower than that of the untreated 



s Nishikado, Yoshikazu, and Miyake, Giiehi. Momidane no shodoku narabini ine-gomahagareby6 

 no yoboho. [Disinfection of seed rice in relation to the prevention of Helminthosporium rice blight.] 

 1. Momidane no onto shinsekiho. [Hot-water treatment of seed rice.] In Byochfi-gai Zasshi (Jour 

 Plant Protection), V. 5, no. 9, p. 693-712 (1-20). 1918. 



