220 BREEDING CROP PLANTS 



approached in calyx or corolla characters the conditions found in 

 S. tuberosum cultivated varieties. Progeny of seed of cultivated 

 varieties showed Mendelian segregation, but no characters were 

 obtained which had not been observed in ancient cultivated 

 varieties. Wittmack (1909), after a careful botanical study of 

 species, reached the conclusion that S. tuberosum was the stem 

 species from which all cultivated potatoes arose. 



The evidence presented by De Candolle (1886) seems sufficient 

 to prove that the potato was wild in Chile and in a form which 

 is very similar to that of our cultivated plants. Heckel (1912) 

 reports a study of changes under cultivation of Solatium tubero- 

 sum forms collected in the wild in Bolivia and Peru by M. Verne. 

 The wild plants were 0.25 meter in height, bore blue flowers and 

 deep green foliage and tubers about the size of a hazel nut each 

 produced at the end of a long stolon. These tubers were planted 

 at Marseilles in a garden heavily fertilized with manure. Little 

 change was observed in flower and fruit characters but there were 

 pronounced changes in the subterranean parts. The yellowish 

 tubers, each borne at the end of a much shortened stolon, con- 

 tained a much greater amount of starch than wild tubers, while 

 the characteristic bitter taste of the wild tubers disappeared. 

 Much more profound changes occurred under cultivation with 

 tubers of S. maglia (Heckel, 1909). 



There seems to be no good reason for speaking of all these 

 tuber changes as mutations. It seems more in line with modern 

 genetic usage to consider them as the normal expressions of the 

 inherited factors under the new conditions of environment 

 which occur under cultivation. 



The cultivated potato was first introduced into Spain and 

 Portugal by the Spaniards during the first half of the sixteenth 

 century. 1 Clusius described and illustrated the potato from 

 plants sent him in 1588 by the governor of Mons. The published 

 description was made in Clusius' "Rariorum Plantarum Histor- 

 ia" which appeared in 1601. The original plant obtained by 

 Clusius bore two tubers and a fruit ball. This variety bore red- 

 dish tubers and light purple flowers. The spread from this in- 

 troduction was probably next into Italy and from there early in 

 the seventeenth century to Austria, then to Germany, from Ger- 

 many to Switzerland and then to France. 



Drake, after a West India piratical trip, took back the Roanoke 



1 EAST, 19086. 



