SEEDLIXG BLIGHT A:iSrD STACK-BURX OF EICE. 



the hot-water treatments, tests were made to determine the per- 

 centages of rice carrying these fungi internally. The kernels were 

 carefully dehuUed, treated 3 to 5 minutes in 50 to 70 per cent alcohol, 

 then soaked for 10 minutes in a 1 to 1,000 solution of mercuric chlorid, 

 and placed in tubes of sterile agar (PL IV) or on sterile agar or 

 blotter paper in Petri dishes (PL VI) after washing thoroughly in 

 sterile water. The results of these tests are given in Table 1. 



Table 1. — Internal infection of rice seeds after surface sterilization in crop varieties groum 



at Crowley, La., in 1919. 



Variety. 



Seeds 

 treated. 



Seeds infected. 



Variety. 



Seeds 

 treated. 



Seeds infected. 



Number. 



Per cent. 



Number. 



Per cent. 



Honduras 



261 

 60 



197 

 42 



75.48 

 70.00 



Carolina White... ' 4S 



46 

 32 



95.84 



Wataribuiie. . 



ShinriM.. 



48 



66.66 













The rice for the tests referred to in Table 1 was taken from the 

 stock seed supply at the Rice Experiment Station, Crowley, La., in 

 the fall of 1919, and the tests were made during the following winter. 

 During the spring of 1920 seeds from a larger number of the best 

 varieties of rice were tested to determine their relative susceptibility 

 to internal seed infection. Of each variety obtained from the seed 

 lots at the Crowley rice station 100 seeds were dehuUed and their 

 surfaces sterilized; then they were washed thoroughly in sterile water 

 and placed in sterile moist chambers on damp filter paper. They 

 were allowed to incubate at room temperature for seven days, and 

 the percentages of germination and infection were then taken. No 

 attempts were made to identify the fungi from each kernel. The 

 results of these tests are given -in Table 2. 



Table 2. — Germination and internal infection of rice seeds grown at Crowley, La., in 1919. 



Variety. 



Germi- 

 nation. 



Infection. 



Variety. 



Germi- 

 nation. 



Infection. 



Per 

 cent. 



Per 



cent. 



Degree. 



Per 



cent. 



Per 

 cent. 



Degree. 



DeUtus (large shocks) 



DeUtus (small shocks) 



Blue Rose 



86 

 64 

 92 

 99 

 53 

 92 

 83 

 63 

 95 



50 

 79 

 41 

 35 

 83 

 25 

 91 

 92 

 38 



SUght. 

 Heavy. 

 SUght. 



Heavy. 

 SUght. 

 Heavy. 



Do." 

 SUght. 



Tokalon.. . 



84 

 50 

 81 

 66 

 99 

 98 

 69 

 99 

 98 



38 



95 



65 



49 



9 



7 



70 



25 



8 



SUght. 

 Heavy. 



SUght". 



Evangeline 



Acadia. 



Vintula 



Early ProUfic 



Honduras 



Wataribune 



Honduras (CaUfornia) 



Wataribune (CaUfornia).. 

 Early ProUflc (Louisiana) 



Honduras (CaUfornia) 



Wataribune (California).. 



Do. 

 Do. 



Carolina Gold . . 



Heavv. 



Shinriki 



SUght". 



Fnrtiina 







In Table 2 the Delitus variety was obtained from both large and 

 small shocks. The harvest season was a very wet one, so the grain 

 in the small shock was injured much more than that in the large or 

 normal shock. The terms ''slight" and ''heavy," referring to the 



