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Journal of Agricultural Research v 0 i. xxvm, no. 3 
COTTONSEED OF THREE CLASSES 
After much study of the problem, it was clear that in cottonseed there are 
three distinct classes of samples: 
1. Strong samples in which a large percentage of the seeds will germinate 
well under a wide range of conditions (PL 1, A). 
2. Samples which contain many dead or weak seeds which always fail to 
produce healthy seedlings (PL 2, A). 
3. “Sensitive” samples, in which a large percentage of the seeds are viable 
and capable of producing seedlings, although there is a tendency for the seeds 
to succumb under unfavorable conditions of germination (PL 1, C). 
The first two classes offer no difficulties to the analyst, so it is the third class 
which interests us here. It is especially important because a large per cent of 
the samples of some varieties received from Texas during the past two seasons 
have belonged to this “sensitive” class. 
When sensitive samples are germinated by the standard method, the entire 
test is often covered by a growth of fungus, many of the young sprouts are water- 
soaked and decayed, and in many of the remaining seeds the hypocotyl decays 
before it has a chance to break through the seed coat. From the fact that other 
samples of the same variety, grown on the same tray, show no tendency to mold, 
and consistently give, high germination results, it is clear that the mold and decay 
do not result from contamination of the substratum or of the germinator. 
RELATION OF MOLDS AND BACTERIA 
An examination by Dr. Chas. Dreschler, of this Bureau, of seedlings from 
both soil and laboratory germination tests of sensitive samples failed to reveal 
the presence of any organisms definitely connected with recognized diseases of 
cotton. However, a beginning has been made of a study of the various organisms 
actually present on the seeds and their possible relation to the decay of the 
seeds- and seedlings. * 5 On the surface of the seeds were found many species of 
bacteria, and several fungi, the most common being Rhizopus nigricans. Surface 
sterilization of the dry seeds with Hg Cl 2 (1:1,000) for 30 minutes gave com¬ 
pletely sterile seeds. However, seeds which had been in the germinator for 24 
hours or longer and were then surface sterilized in the same manner, revealed 
the presence within the seeds of Rhizopus sp. and numerous bacteria—all com¬ 
mon soil organisms. 
SENSITIVE SAMPLES NOT THE RESULT OF “HEATING” IN 
STORAGE 
It was at first suspected that the tendency of some samples of cottonseed to 
mold and decay during germination was due to “heating” in storage. Although 
a study of the moisture content and temperature of stored cottonseed in Texas 
in the fall of 1922 gave no evidence of the occurrence of “heating” of the seed, 
sensitive samples were very prevalent in that season. Damage to cottonseed 
from “heating” does occur, as has been described in a report of the Arkansas 
Agricultural Experiment Station, 6 but lt heating” of the stored seed is not the 
cause of the “sensitive” condition of much Texas cottonseed. 
» The writers are indebted to N. R. Smith, of this Bureau, for help with materials and methods, and 
for the identification of organisms. 
6 Knapp, B.— the effects of methods of harvesting and storing on cottonseed. Ark. Agr. 
Exp. Sta. Bui. 181: 23. 1922. 
