28 Colour and other Characters in the Potato 



" shallow " or " deep." The " shallow " eye is a superficial eye, i.e. the 

 central growing point is not depressed but is level with the general 

 surface of the tuber and the brow is but very slightly marked. 



Typically " deep " eyes are those of " Congo " and most of the 

 family K ("Congo" x " Flourball" seedling) and ^"'", whilst typically 

 "shallow" eyes are seen in A-~ ; H' x A, Nos. .5, 37, 41. The "shallow" 

 eye is a distinctive and an easily recognized feature. Briefly the 

 "deep" eye is dominant to the "shallow," and the heterozygous "deep" 

 eye is never quite so "deep" as the typically "deep" one. In "Flour- 

 ball" the eye is "deep" but not remarkably so; of its seedlings 14 

 out of 43 were definitely "shallow." In the family A, of 98 seedlings 

 21 were "shallow," and A the parent may be regarded as having the 

 standard impure "deep" eye. 



The D^ X A families contain 16 "shallow"- and 33 "deep "-eyed 

 individuals. 



The H^ X A families contain 22 "shallow"- and 71 "deep "-eyed. 

 K^ is a further example of an impure dominant "deep "-eyed potato. 

 Of the 73 seedlings of this family 23 are " shallow " and 51 " deep." 



Two F'^ families were raised from the cross of " Red Fir Apple " x 

 " Reading Russet." These two families differ a little in respect to 

 the eyes. Both were raised respectively from sister tubers of the indi- 

 vidual F^ plant (i'). Both parent plants grown from these tubers had 

 "shallow" eyes, one family, Z"''', consists of 54 individuals, all of which 

 carry " shallow "-eyed tubers. In the other family, X'"', Plate XXIII, 

 out of 55 individuals 5 (Nos. 4, 15, 51, 52, 59) must be described as 

 medium, i.e. the eye is distinctly depressed and the brow is evident, 

 though not heavily developed. The only other " shallow "-eyed potato 

 that was selfed was " Bohemian Pearl," all the individual plants which 

 have arisen from it that have come under my notice are " shallow "- 

 eyed. Of the first generation there were some hundreds, of the second 

 only five. 



If all the families arising out of matings of impure dominant eyes 

 be put together, we obtain the following : 



"Flourball" seedling selfed 



A 



D^ X A 



W X A 



H'O X A 



K» 



Total ... 91 to 265 



This is almost exactly 1 : 3. 



