A STUDY OF SWEET POTATO VARIETIES. 23 
the time of digging. It has not been possible for the writers as 
3 7 et to test the different varieties in this respect. 
In considering the table qualities of the sweet potatoes canned im- 
mediately after digging and of those canned after the usual curing 
and storage, preferences, so far as it has been possible to obtain 
them, seem to favor the latter, since in the curing and subsequent 
storage the sweetness increases and the distinctive flavors become 
more fully developed. For certain culinary uses, however, the 
firmer product from the freshly dug potatoes would be more adapt- 
able ; and those persons favoring a dry potato would doubtless find 
that the physical qualities obtained would more than offset the added 
sweetness and flavor. 
When canned after curing and storage, the soft-fleshed varieties, 
like the Nancy Hall, Porto Rico, etc., yield during the canning 
process a liquid which is quite sweet. This is what gives to these 
varieties their moist appearance. The presence of this liquid does 
not signify a high moisture content, however, for in these varieties 
the moisture may be actually lower than in that of the Big-Stem 
Jersey and others of the firm types. The proportion of starch pres- 
ent seems to account largely for this condition. 
VARIETIES AND STRAINS OF SWEET POTATOES USED IN THESE 
TESTS. 
The following brief descriptive list of the varieties and strains 
of sweet potatoes used in these studies is given not for its taxonomic 
value but to assist the practical worker in the selection of suitable 
varieties to meet particular needs. Those interested in the classifi- 
cation of the sweet-potato varieties should consult the work of 
Thompson and Beattie {19). 
The statements regarding vine and root characters are based upon 
the work of the above authors, confirmed by field observations. 
The productiveness of varieties and strains is indicated by terms 
descriptive of results obtained at the Arlington Experimental Farm, 
it being recognized that yields vary considerably under different 
climatic and soil conditions. 
The terms defining the color of the skin, flesh, and cooked potato 
are taken from the work of Ridgway , 3 with the colored plates of which 
the writers have made direct comparisons. Skin colors may vary 
with different soils. The colored plates found at the end of this 
bulletin (Pis. I to III) show the shades of color of the canned 
product of the different varieties here listed. 
Firmness and softness of the canned product have been graded 
under the heads " very firm," " firm," " medium firm," " medium 
3 Ridgway, Robert. Color Standards and Color Nomenclature. 43 p., 53 pi. (col.). 
Washington, D. C. 1912. 
