1908.] IMPROVEMENT OF THE POTATO. 431 



ity of the sprout produced varies directly as the size and depth 

 of the eyes, which is worthy of note in selection, otherwise types 

 might be bred with eyes too shallow. 



The number of eyes has a marked effect on the quality, due to 

 the fact that the internal medullary extends a branch to each eye. 

 This makes the quality, other things being equal, vary inversely 

 with the number of eyes. This variation within the variety is 

 very great, varying in a count of 219 tubers of Rural N'ew Yorker 

 No. 2 from 7 to 28. 



In 1902, in the course of this work, 189 tubers of the variety 

 Rural New Yorker No. 2 had been analyzed and a large number 

 having been cooked were found to be of very good quality al- 

 though the average dry matter content was only 20.74 percent. 

 The modes for eyes in this lot was 12. 



TABLE 9. VARIATIONS IN NUMBER OF EYES IN RURAL NEW YORKER No. 2, 1902 



No. of eyes 7 8 9 10 11 12 13 14 IS 16 17 18 19 20 21 22 

 Frequencies 3 4 9 15 21 32 15 20 13 19 12 13 6 4 2 1 



In 1903, 219 tubers of the Early Ohio variety were used, and 

 were found to be of much poorer quality than those used in 1902, 

 though of similar size and of pleasing appearance. The average 

 dry matter content was only 16.15 percent or 4.59 percent lower 

 than the others. The mode for the number of eyes zvas here 15 

 as compared to 12 in the better variety. 



TABLE 10. VARIATIONS IN THE NUMBER OF EYES IN EARLY OHIO, 1903 



No. of eyes 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 

 Frequencies 142 6 21 21 25 36 37 17 12 15 7 11 2 2 



6. Type of soil. It is well known that the physical type of 

 soil best suited for the growth of potatoes is a light sandy loam. 

 These investigations from 1902-1904 were carried on in the black 

 heavy loam characteristic of the corn belt of the central west and 

 in 1905-1906 on a light sandy loam in Connecticut. No stock 

 from the same strain was available for test, and as the influence 

 due to climate and soil is unknown, we have scarcely a warrant 

 to make comparisons. Published analyses, however, show a 

 higher percent of dry matter in potatoes grown on the light sandy 

 loam ? and the quality of tested tubers from the same variety 



