R N. Salaman 11 



pollen. Two individuals of the F^ family were fertilized by a derivative 

 of " Flourball A," very rich in pollen, and gave rise to 39 plants, 19 of 

 which bore pollen and 20 bore none : the expectation on the assump- 

 tion that sterility is dominant being here equality. 



In the "Congo" potato the anthers are entirely devoid of pollen, 

 though they are not usually aborted or crippled. A plant of this 

 variety was crossed by a " Flourball " seedling, and out of 18 ^^ plants 

 which flowered, 8 had abundant pollen and 10 had none : here again 

 the expectation was equality, " Congo " being heterozygous in sterility. 

 Two F^ plants possessing abundant pollen were selfed, and of 44 

 plants examined, 41 possessed pollen and 3 possessed but a few grains 

 of immature pollen. Why these plants should not have borne a fair 

 quantity of pollen seeing that the F^ parents must have been recessives 

 and should have bred true, it is not possible to say. All three 

 examples came out of one family. 



A second cross with " Congo," viz. by " Reading Russet," gave only 

 a small F^ family, three plants bearing flowers, two containing pollen, 

 and one none. 



Similar results were obtained in the cross " Red Fir Apple " and 

 " Reading Russet," F^ being part pollen producers, part sterile, whilst 

 jP*, from the pollen bearing F^, gave 9' plants all pollen producers. 



The flower of the " Red Fir Apple " is heliotrope in colour and the 

 anthers are aborted. 



" Queen of the Valley " has heliotrope flowers with sterile anthers. 

 Crossed by " Flourball " one plant gave a series of F^ plants of which 

 some bore pollen and others none, although exact notes as to their 

 characters in this family were not taken. One of the F^ plants was 

 crossed by a " Bohemian Pearl " seedling, and gave rise to a long line 

 of pollen producers. 



The heredity of male sterility in the potato is obviously the converse 

 of that described by Bateson in the Sweet Pea, for the condition here 

 is distinctly dominant. Bateson found it partially coupled mth green 

 axils in certain families. In the case of the potato, the only evidence 

 of sterility being coupled with any other character was of a negative 

 sort. Working with a large number of established varieties as well as 

 with those plants which arose in the course of this work, I never found 

 a plant possessing pale heliotrope flowers that had other than sterile 

 and contabescent anthers, whilst those that were further tested proved 



^ In 1910 22 more F- plants flowered and all possessed pollen in the anthers. 



