Treatment of Cotton Seed 
table VII 
Per Cent op Cotton Seedlings Infected With 
Anthracnose Growing From Seed Previously 
Heated at 70° C. 
Exp. No. 
Lot No. 
Duration of 
Treatment, Hrs. 
Per Cent 
Anthracnose 
Treated Seed 
Check 
1 
1 
1 
44 
2 
1 
24 
2 
20 
2 
2 
48 
1 
20 
When seed had been heated at 70° for one hour, 44 per cent of the 
seedlings developed anthracnose. After seed had been heated 24 hours, 
the percentage of seedlings which became diseased was reduced from 20 
per cent in checks to 2 per cent in the treated. 48 hours at 70° C. did 
not suffice to completely free the seeds of anthracnose. Manifestly, a dry 
air temperature of 70° C. causes a great reduction in the amount of 
anthracnose appearing on seedlings from diseased seed, but fails to elim¬ 
inate the disease within a period of time sufficiently short to obviate 
injury to seed containing a normal amount of water. 
When it became apparent that the application of temperatures of 70, 
SO, 90 and 100° to cotton seed for periods of time sufficiently long to de¬ 
stroy the anthracnose fungus brought about marked reduction of germinative 
power of the seed, tests were made to determine whether decrease of the 
normal water content by desiccation at temperatures too low to be harm¬ 
ful would increase the resistance of the seeds to high temperatures. 
Accordingly, cotton seed having a normal air dry water content was 
stored over H,S0 4 or Ca0 2 in desiccators or dried in ovens at temperatures 
of 40, 50 or 60° C. for varying periods of time. After this preliminary 
desiccation, the seed were heated at temperatures of 60, 70, 80, 90 or 100° 
C. for certain periods of time. Such of these tests as deal only with water 
relations of treated seeds will be described and the results given in detail 
in a later section, Part II, of this paper. It will suffice to state at this 
point that drying of seeds at low temperatures enables them to endure 
for long periods of time temperatures which otherwise would have been 
Quickly destructive. The following paragraps will be devoted to a 
consideration of the effect of this treatment on the viability of the seed-borne 
elements of the cotton anthracnose fungus. A large number of experiments 
have been made with seed grown in six different seasons. These tests 
are grouped, in accordance with the particular high temperature used and 
the results are set forth in appropriate tables. 
Table VIII presents the data derived from a number of tests in which 
highly infected cotton seed were dried in ovens at 40-45° C. and subsequently 
heated at 60° C. for varying periods of time. 
