6 
BULLETIN 916, U. S. DEPARTMENT OF AGRICULTURE. 
Serious injury was apparent in this experiment. Injury occurred to 
five specimens of Triumph, six of Irish Cobbler, five of Spaulding 
No. 4, four of American Giant, one of Eural New Yorker, two of 
Eusset Rural, and one of Green Mountain. The most serious injury 
occurred in the early-maturing varieties. In experiment No. 6 six 
tubers of each variety were held 96 hours, with injury occurring to 
two specimens of Triumph, two of Irish Cobbler, two of American 
Giant, and one of Eusset Eural. The Spaulding No. 4, Eural New 
Yorker, and Green Mountain varieties suffered no injury. The aggre- 
gate injury in this experiment was 17 per cent, while in experiment 
No. 5 the injury totaled 31 per cent. 
Table II. — Freezing injury to seven varieties of potatoes lieM at 28° F. far 
different lengths of time. 
Number of experiment and duration of exposure. 
Variety. 
No. 1, 7 
hours. 
No. 2, 24 No. 3,48 
hours. hours. 
No. 4, 48 
hours. 
No. 5, 70 
hours. 
No. 6, 96 
hours. 
Num- 
ber of 
speci- 
mens. 
Num- 
ber 
in- 
jured. 
Num- 
ber of 
speci- 
mens. 
Num- ; Num- 
ber j ber of 
in- ! speci- 
jured. mens. 
Num- 
ber 
in- 
jured. 
Quan- 
tity of 
speci- 
mens. 
Num- 
ber 
in- 
jured. 
Num- 
ber of 
speci- 
mens. 
Num- 
ber 
in- 
jured. 
Num- 
ber of 
speci- 
mens. 
Num- 
ber 
in- 
jured. 
2 
2 
2 
2 
2 
2 
2 




1 


20 
20 
20 
20 
20 
20 
20 

2 

I 

2 
2 
2 
2 
2 
2 
2 
• 



1 


Bush. 

11 
11 
11 
11 
11 
11 
11 
5 
6 
5 
4 
1 
2 
1 
6 
6 
6 
6 
6 
6 
fi 
2 
Irish Cobbler 
2 
Spaulding No. 4 — 
American Giant 
Rural New Yorker. 
Russet Rural 
2 
I 
1 





2 

1 

Total 
14 
1 
140 , 3 14 i 1 2 : j 77 24 1 42 ; 
In no case at 28° F. were the potatoes frozen solid. A superficial 
examination would not have revealed an}' evidence of freezing injury 
in any of these varieties. It is true that during subsequent storage, 
however, these internally injured specimens are the first to break 
down, although these potatoes do not show injury so far as their 
external appearance is concerned and would be as salable in the 
ordinary market as the uninjured ones. After a few days at ordinary 
room temperature they are quite unfit for food. While no serious 
injury occurred till the potatoes were held at least 70 hours, isolated 
cases of freezing injury did occur even when potatoes were held only 
7 hours. It is difficult to explain these isolated cases. For some 
unknown reason certain individuals seem to bear much less under- 
cooling than others of the same variety. Similarly, certain varieties 
bear less undercooling than other varieties. There is a certain va- 
rietal difference shown here. The Irish Cobblers seem to be the 
first to succumb to freezing injury, followed by the Triumph, Ameri- 
can Giant. Spaulding No. 1, and Eusset Eural varieties. The Eural 
New Yorker and Green Mountain varieties are the most resistant. 
