Treatment of Cotton Seed 
6 
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INDUCED SECONDARY DORMANCY OF COTTONSEEDS 
In addition to the increase in length of life of the anthracnose fungus as the 
result of storing diseased cotton seed in desiccators kept at room tem¬ 
perature, an induced secondary dormancy of more or less prolonged dura¬ 
tion was observed to occur in a considerable proportion of the stored seeds. 
The results of these germination tests are given in part of Table VI. 
In Experiment 1, lot 1, 46 per cent of the seeds germinated in 2 days; 
54 per cent in 3 days; 62 per cent in 4 days and 62 per cent in 9 days. 
The seeds were not examined again until the 17tli day at which time 66 
per cent had germinated. 17 seeds had not germinated by the end of 
17 days. Seven of this number were covered with fungus, the seed coats 
being soft and the embroys dead and partially decayed. Eight of the 17 
seeds had seed coats which were extremely dry within and much harder 
than those of untreated seeds. These seeds had not swollen and had im¬ 
bibed no water as indicated by the dry condition of the surface of the 
embryo. When the hard seed coats were removed and the dry embryos 
were placed on moist blotting paper, 7 of the 8 seeds germinated and pro¬ 
duced hypocotyls varying from 1 to 15 mm. within 24 hours, and all germ¬ 
inated in 3 days. The remaining two of the 17 seeds had already im¬ 
bibed considerable water, the coats being soft and the embryos moist when 
the seeds were removed from the germinator on the 17th day. These two 
seeds also germinated promptly when their testas were removed. Obviously, 
they had already overcome the dormancy imposed by their dry seed coats 
and were at the point of germination when the seed coats were removed. 
In lot 2, which lost 10.8 per cent of its weight while it was in the 
desiccator, 8 per cent of the seeds germinated in 2 days and 50 per cent 
in 4 days. Thereafter the percentage of germination increased very slowly 
until it reached 80 per cent on the 39th day. No further increase had oc¬ 
curred by the 48th day and the seeds were then removed from the test 
tubes. Six of the 10 which had not germinated were dead and covered 
with fungous growth while 4 possessed seed coats which were hard and dry 
within and had apparently absorbed no water. The testas were removed and 
the seeds were put on moist blotting paper whereupon all germinated and 
produced radicles about 3 cm. in length within 3 days. In lot 3, germination 
increased from 64 per cent on the 6th day of 70 per cent on the 17th day 
while 98 per cent of the seeds of the untreated check germinated in 6 days 
By the 27th day, 15 of the desiccated seeds had failed to germinate, 7 
having hard and dry testas and 8 being dead. The 7 seeds with hard testas 
germinated at once when seed coats were removed. In lot 4, the germination 
increased from 62 per cent on the 9th day to 74 per cent on the 41st day at 
which time all the remaining ungerminated seeds were dead, while 96 
per cent of the untreated check germinated in 9 days. In lot 5, which had 
been in the desiccator 356 days and had. lost 11 per cent of its, weight as 
water, the percentage of germination increased by slow increments from 
64 per cent on the 5th day to 90 per cent on the 139th day, by which time 
all remaining seeds had died. The untreated check gave 82 per cent of germ¬ 
ination in 6 days. 
