168 

 7. Potato Breeding* 



Potatoes are grown in Sweden for four distinct purposes, viz., for 

 cooking, for the production of commercial starch, for cattle food and for the 

 manufacture of spirits. 



For cooking purposes quality and flavor are first essentials; for the 

 production of starch, sorts are required which are particularly rich in this 

 ingredient, while for cattle food, sorts which are high-yielding but not neces- 

 sarily of high quality are sought. In all cases of course productiveness is 

 a primary requisite. 



The average annual production of potatoes in Sweden during the period 

 1891-1900 is given as approximately 2,700,000,000 pounds. The average 

 yield per acre during the years 1891-1900 amounted to 16,607.1 pounds as 

 against 19,916.7 for the whole of western Europe.** During the past few 

 decades the cultivation of potatoes in Sweden has not materially increased, 

 a fact which is believed to be due in part at least to the decrease in the manu- 

 facture of spirits. The importation of potatoes on the other hand, while not 

 large, is nevertheless said to have been on the increase. This fact perhaps 

 more than any other, served to draw the attention of the Swedes to the 

 unsatisfactory position of the potato growing industry within the country 

 and indicated the need, not only for more intelligent methods of cultivation, 

 but for better material in the way of sorts which were better suited to Swedish 

 conditions and which possessed greater power to resist the many diseases 

 which attack this crop. In 1903 the Association at Svalof accordingly took 

 up potato-improvement work as a special branch of its activities with Mr. 

 Joh. F. Lundberg as expert in charge. Owing to certain unavoidable hin- 

 drances however, the normal development of this work was delayed until 

 about 1908, since which time it has advanced rapidly. 



In the prosecution of potato work the principles observed are somewhat 



Principles of different from those recognized in the case of cereals and pease. In the 



provem \ cage ^ ^g j a ^ er cro p s reproduction is entirely by means of seed which 



breeding reproduces true and for the most part without hereditary variation, 



providing natural crossing does not occur. In the case of the potato on 



the other hand, reproduction commonly takes place in a vegetative way by 



means of tubers. These are simply specialized parts of the underground 



stems stored with starch and covered with buds or "eyes." When the tuber 



or a portion thereof is planted under favorable conditions, the buds begin to 



grow, the food being at first drawn from the tuber itself but eventually from 



the soil. 



While the peculiarities of the mother plant are ordinarily reproduced 

 by means of tubers, without any apparent deviation, yet variations frequently 

 occur. These variations are commonly regarded as modifications induced 

 by external agencies such as soil, climate, food supply and disease. Whether 

 or not the type may be changed by the selection of such modifications has 

 long been a matter of much speculation. In his work with barley and beans 



* The data on work with potatoes as submitted herewith, have been obtained chiefly from publica- 

 tions, including annual reports, by Lundberg. 



** "Sveriges Land och Folk," Gov't. Printing Office, Stockholm, p. 537. 



