6 Nebraska Agricultural Exp. Station Research Bul. 16 
10. Death from freezing is directly related to the moisture 
content of the kernel and also to the duration of the exposure 
to cold. Seed corn maturing in a natural way becomes cold 
resistant progressively as its moisture content diminishes. Seed 
corn mortality increases progressively as the duration of the 
killing temperature is extended. Seed corn samples containing 
various amounts of moisture were husked from the field and 
subjected artificially for twenty-four hours to various freezing 
temperature ranges. After freezing, parts of each sample 
together with corresponding unfrozen samples were allowed to 
thoroly cure, after which germination tests were made. 
The relative germination of the frozen and the unfrozen 
samples indicates the degree of freezing injury upon the viability 
as follows: 
Tempera- Moisture Content of Grain (Per Cent) 
ture 
Ranges 
10-15 
15-20 
20-25 
25-30 30-35 35-40 40-45 45-50 50-55 
55-60 60-65 
Degrees F. 
Relative germination {Per cent ) 
32 to 28. . 
100 
85 
75 
71 
69 
33 
31 
0 
24 to 20. . 
100 
96 
77 
67 
13 
12 
12 
6 
0 
0 
16 to 12. . 
100 
88 
34 
12 
0 
0 
0 
0 
0 
0 
8 to 4 . . 
100 
98 
47 
7 
0 
0 
0 
0 
0 to -5 . . 
97 
63 
0 
0 
0 
0 
0 
' 0 
0 
' 0 
0 
Where data are lacking no tests were made. 
11. The vitality of corn containing from 15 to *20 per cent 
of moisture will not be injured by ordinary autumn freezing; 
and corn with 10 to 14 per cent of moisture will stand the 
most severe winter temperatures without injury to its germin- 
ative power. 
12. The kernels upon an ear of corn may vary in moisture 
content which may explain partial germination of an ear of 
corn after exposure to freezing temperatures. 
13. Ice formation within the kernel is not necessarily fatal 
to the vitality of the germ. 
14. The variation in time of freezing weather together 
with the great seasonal variation in time of corn maturity 
makes freezing injury inevitable in occasional years. 
15. The best adapted types of corn for Nebraska condi- 
tions should ripen two or three weeks before the mean date of 
the first killing frost for the locality in which they are grown. 
16. Varieties which ripen too late may be made to ripen 
earlier (1) by field selection of seed from the earlier maturing 
