POTATO BEEEDIXG AXD SELECTIOIST, 19 



ill May, it is desirable to sow the seed in the greenhouse about March 

 20 to 25. (PL y.) The plants are usually spaced in the field in rows 

 3 feet apart and are set 2^ feet apart in the row. (PL VI, fig. 1.) In 

 the ensuing year the tubers are spaced 18 inches apart in the row. 

 (PL VI, fig. 2, and PL VII, fig. 1.) 



The method which has been pursued in determining the merits of 

 the seedluigs which have been grown by the Department of Agri- 

 culture since 1910, soine 60,000 in all, has been rather more compre- 

 hensive than is considered advisable from a commercial standpoint. 

 Out of some 28,000 seedhngs grown in 1910, nearly 19,000 developed 

 tubers; most of the remaining 9,000 either failed to grow after being 

 transferred from the greenhouse to the open ground or else they 

 failed to produce tubers. All of those which developed tubers 

 were saved, described, and grown in 1911. At harvest time aU were 

 again saved for further study and description. This entailed a large 

 amount of work and the recording of many data. Some idea of the 

 way in which these studies were performed may be secured from 

 Plate VII, figure 2. The object in taking so many data and in grow- 

 ing a large number of seedlings which would ordinarily be discarded 

 was to note whether an}' change occurred in the seedhng in the second 

 and subsequent generations. In other words, it was thought desirable 

 to determine whether one might safely discard all unpromising 

 looking seedlings the fii'st season. The results secured indicate that 

 there is fit tie likehhood that a first-year seedling producing pronged, 

 irrogidar-shaped tubers similar to those in Plate VIII, figures 1 and 2, 

 will ever develop into a smooth-tubered variety. It is also equally 

 apparent that a deep red or blue skimied seedling is never likely to 

 become a desirable commercial variety. On the other hand, the 

 hybridist is not always justified in discarding a seedling which has 

 produced only two or three small tubers, weighing in the aggregate 

 possibly not over 1 ounce, provided the tubers are smooth, shapely, 

 and white skinned . (PL VIII, fig. 3) . It is an easy matter, however, 

 to decide on the advisabihty of retaining such seedlings as those shown 

 in Piute IX. Occasionally a seedling is found that is unusually 

 prolific in both tubers ajid seed balls; such a potato is shown in 

 Plato X. 



The data secured from the J9I0 and 1*911 seedlings have served to 

 jiiake it possible to discard first-year seedlings rather freely, with a 

 fair degree of reliance, it is believed, both with respect to those dis- 

 carded and those retainecL 



These seedlings were tested in 1913 and 1914 at three nxther widely 

 -epurated points — Houlton, Me., 1913; Caribou, Me., 1914; Iloneoyo 

 I''alls, N. Y., and Jerome, Idalio. Of the 35,000 s(M',(lling])lantM grown 

 in 1910 and \'.)\ I, there now remain less than 150 numbers at the first 

 two points uihI about 120 at the last point. Since 1911 the practice 



