MUTATIONS OF THE POTATO 



TWO SOMEWHAT UNSTABLE LEAF-FORM SPORTS OF THE 



IRISH POTATO 



Donald Folsom 



Maine AgnciiUnral Experiment Station, Orono 



^^^i^if 



MUTANT AND NORMAL LEAVES 



Figure 19. While greater variation is to be expected in the progeny of plants that repro- 

 duce by seed, the breeder of those that are propagated vegetatively also has an opportunity 

 to take advantage of variation, in the form of bud sports. Frequency of sporting varies greatly 

 in different species ; in the study here reported only five leaf-form mutations were observed 

 in more than 350,000 .plants examined. The leaves shown above are both from the same 

 plant, the fifth vegetative generation of a thick-leaved mutant discovered in the Green 

 Mountain variety. The leaf on the right is typical of the mutant form, while the other has 

 partly reverted to the normal. 



VARIEGATION sports of the 

 Irish potato have been reported 

 by Quail jer'* and by Hunger- 

 ford," and have been observed by the 

 writer. MacKelvie'' has described a 

 sport with simuUaneous loss of tuber- 



skin color, change of sprout color, and 

 decrease in abruptness of tapering of 

 the distal ends of the leaflets. Leaf- 

 form sports appear to be infrequent 

 in potatoes. The two types reported 

 here seem to be somatic mutations in 



*For numbered references, see Literature Cited at end of article. 



45 



