390 GROWTH OF PLANTS 



Table 40. Cane Sugar Values Showing Response of Tubers of Potato 

 Varieties to Conditions of Storage. Storage Started Oct. 25, 1940 



it is reported by commercial producers that occasional lots fail to de-sugar 

 properly. A favorable temperature for de-sugaring is 27° C (81° F) . Table 41 

 shows the de-sugaring of 13 varieties after storage at 5° C (41° F) for 63, 

 126, and 186 days, followed by storage at 27° C (81° F) for 10, 20, and 

 40 days. 



Let us examine the first five varieties given in this table, both as to the 

 rate at which they accumulate reducing sugar at the low temperature and 

 at which they de-sugar at the high temperature. Irish Cobbler and Green 

 Mountain accumulate reducing sugar rapidly and in large amounts, the 

 former bearing more after 126 days at 5° C (41° F) than after 186 days, 

 and the latter more after 63 days than after either 126 or 186 days. Russet 

 Rural accumulates only a moderate amount of reducing sugar and reaches 

 its maximum after 63 days, showing no further rise after 126 or 186 days. 

 Chippewa forms reducing sugar slowly in cold storage, and continues to 

 increase up to 186 days, when the amount becomes high. All these varieties, 

 except Chippewa, de-sugar rapidly when placed at 27° C (81° F), reaching 

 a content low enough for chip making after 20 days for either 63- or 126-day 

 low- temperature storage. Three of the five varieties show the same after 186 



