174 



THE POTATO 



crop consist of small tubers, the next larger, and so 

 on, does not always hold, as a tuber weighing over 

 seven ounces has been 

 produced the first year. 

 The Burbank potato was 

 full size the first year it 

 was grown from seed, 

 and many breeders feel 

 that unless the tubers 

 are of edible size the 

 first year they are not 

 likely to be worth fur- 

 ther care. Frequently 

 the tubers do not reach 

 full size until the second 

 year.' The tubers from 

 each plant must be kept 

 separate, the best seledled 

 and planted again. The 

 distance apart varies be- 



FIG. 51 — PISTIL OF POTATO 

 I'LOWER, SHOWING THE PARTS 

 — Stigma, where pollen is applied, 

 tween 26x 12 and 40 X *— style, down which the pollen tube 

 V. ^17'^ 1 *- goes to the ovary, c, where it fertilizes 



40 inches. Wiaer plant- the ovule, which become the seeds (see 

 ing permits the study of I'ig- 3>- rf— Attachment of stamens, 

 , . ,. . , - rtAi removed to prevent self-fertilization, 



the inaiViauai. ine ^_petals, partly torn away to expose 



third, fourth, and fifth ovary, /—sectional view of calyx. 



year field culture is given, 



and a variety may be found v/orthy of a name and 

 further trial before distribution. The breeder's aim is 

 to produce varieties which excel in producflivity, 

 power to resist diseases, earliness, quality, percentage 



' Minn. Bui. 87, p. 10. 



