Apr. 19, 1924. 
Germination of Cottonseed 
m 
TEMPERATURE FOR GERMINATION OF COTTONSEED 
As a result 6f a study of the effect of temperature on the laboratory germina¬ 
tion of cottonseed, it was concluded that the excessive molding of sensitive 
samples is not dependent on the temperature of germination, and that the usual 
20°-30° C. (68°-86° F.) alternation (30° C. for 6 to 8 hours and 20° C. for the 
remainder of the day) is probably the best temperature of cottonseed germi¬ 
nation. Cottonseed can be germinated satisfactorily at 20° C. (although 
slowly) at 25° C. (77° F.) and at a 15°-35° C. (59°-95° F.) alternation (35° C. 
for 6 hours and 15° C. for 18 hours). 
A comparison of the usual 20°-30° C. alternation with a similar 18°-32° C. 
alternation and with the reverse alternation (18° C. for 6 to 8 hours and 32° C. 
for the remainder of the day) indicated that the usual 20°-30° C. alternation is 
the most satisfactory both for the rate and for the completeness of germination. 
DEMONSTRATION OF “LIVE SEEDS” IN SENSITIVE SAMPLE 
As has been indicated above, the “.sensitive” samples have been designated 
as such because a large percentage of the seeds can by special methods be dem¬ 
onstrated to be viable although germination by the standard method gives a 
low and variable result. It was found that the “live seed” in these sensitive 
samples could be determined by any one of the following special methods: By 
testing the seeds in soil with controlled moisture content and controlled tem¬ 
peratures; often by soil tests in the greenhouse; by tests in sphagnum moss; 
to some extent by “presoaking” the seeds; by surface sterilizing the seeds; 
and by simply wetting the fuzz of the seeds before putting them to germinate. 
It would seem that any method which will get water into the seeds quickly and 
start germination promptly will prevent the development of mold and the decay 
of the sprouts. 
With the soil method, it is difficult to obtain a soil which will uniformly 
supply the seeds with sufficient moisture. Greenhouse testing in soil is satis¬ 
factory if the temperature can be maintained between 60° and 80° F. Surface 
sterilization of the seeds, either by a dilute solution of mercuric chlorid or by 
dusting with dry copper carbonate powder (as suggested by Prof. A. H. Leidigh 
of the Texas Agricultural Experiment Station) will usually control the mold and 
decay during the germination of these sensitive samples. However, the writers 
have always hesitated to use a sterilizing agent in making tests of the germinating 
power of commercial seeds. Although for the prompt germination of cotton the 
seeds must absorb a large amount of water quickly, an excess of water interferes 
with germination, probably by limiting the supply of oxygen. For this reason, 
presoaking the seeds is uncertain, as often a part of the sample is rendered dormant 
by the process. The simplest and most successful treatment of sensitive samples 
was found to be a thorough wetting of the fuzz of the seeds before they were put 
to germinate. This has been designated the “prewetting method.” This insures 
prompt germination of the seeds and in most cases entirely prevents the spread 
of mold and the decay of the young sprouts. 
A few exceptional samples have been encountered which behave in a peculiar 
manner when tested by the prewetting method. In these samples, many of 
the seeds remain in a dormant condition in the germinator, as they do when 
soaked too long in water. In these cases, the total germination is greater by the 
standard method. Wherever it has been possible to trace the history of such 
samples, it has been found that the development of the seed has been checked 
either by weather conditions or by insect attack. Fresh seeds, which still con¬ 
tain a large amount of moisture, behave in the same way. 
