BULLETIN 1063, U. S. DEPARTMENT OF AGRICULTURE. 
Tabled. — Relation of cut or bruising injury to the keeping quality of sweet 
potatoes. 
[Shrinkage and decav averages for three varieties kept at a temperature 
1917-18 and 1918-19.] 
of 50° to 55° F., seasons of 
Average 
weight at 
harvest 
time. 
Shrink- 
age dur- 
ing 
curing, 
19 days. 
Shrinkage at end of— 
Weight 
at end of 
storage 
period. 
Loss due to decay, 
164 days. 
Variety and 
condition. 
51 
days. 
82 
days. 
111 
days. 
141 
days. 
164 
days. 
Uninjured: 
Big-Stem Jersey. 
Nancy Hall 
Southern Queen. 
Pounds. 
142. 56 
110.00 
153. 09 
Pa- 
cent. 
6.59 
7.14 
7.83 
Per 
cent. 
8.02 
8.46 
9.12 
Per 
cent. 
9.42 
9.69 
10.49 
Per 
cent. 
10.88 
11.03 
12.00 
Per 
cent. 
12.09 
12.12 
13.21 
Per 
cent. 
13.54 
13.10 
14.69 
Pounds. 
123. 25 
121. 56 
130. 59 
Pounds. 
1.81 
.84 
.59 
Per 
cent. 
1.27 
.60 
.38 
Total 
435. 66 
375. 41 
3.25 
Average 
7.23 
8.55 
9.88 
11.33 
12.49 
13.83 
.75 
Injured, cut, and 
bruised: 
Big-Stem Jersey . 
Nancy Hall 
Southern Queen. 
73.25 
46.06 
71.97 
14.44 
18.52 
12.55 
19.75 
21.51 
14.67 
23.59 
23.88 
16.54 
27.09 
26.19 
18.64 
30.33 
27.99 
20.06 
33.83 
29.51 
21.88 
48.47 
32.47 
56.53 
20.16 
4.28 
1.94 
27.52 
9.29 
2.69 
Total 
191. 28 
137. 47 
26. 3S 
Average 
ii.83 
18.26 
21.01 
23.69 
25.91 
28.13 
13.79 
Every potato in the damaged lots was either cut or bruised. Table 
3 shows that for every period the shrinkage of the injured sweet 
potatoes was much greater than that of the uninjured ones. The 
exposure of the cut surfaces and the drying up of the decayed sweet 
potatoes caused a higher shrinkage in the injured lots. At the end 
of the storage period the average shrinkage of the three varieties 
was 28.13 per cent for the injured and 13.83 per cent for the un- 
injured potatoes. The Big- Stem Jersey variety showed the highest 
percentage of shrinkage and also the largest proportion of decay 
in the injured lots. The Southern Queen had the smallest percent- 
age of shrinkage of the injured lots. The extent of decay was con- 
siderably greater in the injured than in the uninjured lots. The 
average loss for the three varieties was 0.75 per cent in the unin- 
jured lots and 13.79 per cent in the injured lots. The greatest loss 
was in the Big-Stem Jersey, being 27.52 per cent in the injured lot 
in comparison with 1.27 per cent for those not injured. The propor- 
tion of decay in the injured lot of the Southern Queen variety was 
very small, being only 2.69 per cent, or less than one-third as much 
as in the Nancy Hall and less than one-ninth as much as in the Big- 
Stem Jersey. It is a matter of common observation that the South- 
ern Queen will stand rough handling better than any of the other 
standard varieties. The cut surfaces of this variety heal rapidly 
under good storage conditions. It should not be inferred, however, 
that great care in handling it is not important, for under less favor- 
able conditions the loss might be much higher. The excessive shrink- 
age and the poor appearance of the injured potatoes reduce their 
market value materially and are of sufficient importance to justify 
