More Potatoes 



347 



abundant and cheap supply for domestic 

 use and a lar^^e exportable surplus. 



With potatoes selling at $3 or $4 a 

 bushel this spring, every householder 

 has been obliged to realize that some- 

 thing is wrong with the American potato 

 supply. The trouble lies partly in bad 



) wmw^ potatoesi 



65 I MAIZE 



>- 



•^7 V/M///, WHEAT 



). . 5j. V-' ; 



BARLEY; RYE ^^"^^ 

 . EZZ2ZZIIL j_ _/| 



FOOD CROPS OF THE WORLD 



The figures show the annual yield in 

 millions of tons, average for five years, 

 1908-1912. Rice is omitted, because 

 the figures from large parts of China, 

 where rice is extensively grown, cannot 

 be obtained. Probably rice belongs 

 between oats and wheat in the above 

 diagram. Data after Gilbert. (Fig. '^.) 



weather and plant-disease, but it is to 

 some extent due to failure to apply 

 knowledge that is the common property- 

 of every plant-breeder. A. W. Gilbert's 

 book on "The Potato,"^ is, therefore, 

 timely, for Dr. Gilbert was long pro- 

 fessor of plant-breeding at Cornell 

 University and chairman of the plant- 

 breeding section of the American Genetic 

 Association, and naturally devotes par- 

 ticular attention to the problems which 

 fall in the field of genetics. 



"The principal method of improving 

 the potato is by bud-selection," Dr. 

 Gilbert says. "Potato hills are v^ery 

 variable, and improvement is made by 

 planting the tubers from the best hills. 

 Many of these apparent improvements 

 may be due to some advantage in 

 growth, such as increased fertility, 

 more light or moisture, and so forth. 

 Of course, this increase is onlv transi- 



tory, and not being inherited, produces 

 no permanent advancement. 



"The potato, however, presents varia- 

 tions which are inherited. These are 

 of two kinds — smaller differences whose 

 inheritance produces a gradual change, 

 and large differences or so-called 'bud 

 sports' or bud-mutants which imme- 

 diately become the starting point of new 

 varieties. 



"Potatoes differ from most farm crops 

 in their manner of reproduction. They 

 are propagated vegetatively without 

 the intervention of a sexual process like 

 corn or wheat. Each hill of potatoes 

 comes from one tuber or part of a tuber 

 which was the product of one bud of the 

 mother plant. Hence the entire hill 

 becomes a unit, and hill selection is, in 

 reality, bud selection. Single tubers 

 cannot be said to be units from the 

 breeder's standpoint. Therefore, it is 

 of supreme importance to take into 

 account the yield of an entire hill and 



BUSHELS OF POTATOES PER ACRE 



Germany and Great Britain get more 

 than 200 bushels of potatoes from an 

 acre of land. The United States does 

 not do half as well as this, but might 

 easily improve its showing. The figures 

 show the average annual yields per 

 acre for the years 1904-1914, after 

 Gilbert. (Fig. 6.) 



not the presence in it of two or three 

 large tubers resulting in low total 

 yield for the hill." 



MASS SELECTION 



"Until recently, the method of selec- 

 tion has been to choose from the potato 



2 The Potato, by Arthur W. Gilbert, Ph.D., formerly professor of plant-breeding. New York 

 vState College of Agriculture at Cornell University, assisted by Mortier F. Barrus, Ph.D., professor 

 of plant pathology. New York vState College of Agriculture, and Daniel Dean, formerly president 

 of the New York State Potato Association. The Rural Science Series (edited by L. H. Bailey). 

 Pp. 318, price SI. 50 net. New York, the Macmillan Co., 66 Fifth Avenue, 1917. 



