A STUDY OF SWEET POTATO VARIETIES, 23 



the time of digging. It has not been possible for the writers as 

 yet 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 

 iirmer 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,^ 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 



» Ridgway, Robert. Color Standards and Color Nomenclature. 43 p., 53 pi. (col.). 

 Washington, D. C. 1912. 



