444 IiEPOKT OF TTIK DEPARTMENT OF HORTICULTURE OF THE 



5. General considerations arising from the experiment are: i. 

 These crosses strikingly contradict the idea that seedling apples 

 revert to the wild prototype. 2. The stimulus of hybridity is 

 very marked in the vigor of the crosses under consideration. 3. 

 The behavior of some of the crosses strongly suggests that ap- 

 ples may be prepotent in one or more of their characters. 



6. The inheritance of a number of characters is discussed; 

 namely, color of skin, color of flesh, shape, size and acidity. 



7. In color of skin, the fruits in which yellov/ predominates 

 over red seem from the data in hand to be in a heterozygous 

 condition for yellow and red. The fruits in which red predomin- 

 ates are either homozygous or heterozygous. The pure yellows 

 are homozygous. 



8. The data are not at all conclusive as to color of flesh but 

 suggest very strongly that Ben Davis and Mcintosh, crosses of 

 which gave the best opportunity of studying color of flesh, both 

 carry yellow and white, the white being recessive. 



9. Establishing the laws of inheritance of size and shape in 

 apples promises to be a most difficult task, since these characters 

 depend upon so many external as well as internal conditions. 

 The data from these crosses favor the supposition that these 

 characters are inherited practically as intermediates. 



10. The study of the inheritance of sweetness and sourness is 

 based wholly upon crosses of sub-acid varieties. The fact that 

 sweet apples appear in nearly all of the crosses is significant. 

 The crosses are so few that the exact 3:1 ratio could hardly be 

 expected in all cases, yet the total progeny indicates strongly 

 that crosses of these sub-acid varieties break up in the propor- 

 tion of three sour apples to one sweet one. 



11. The following is a summary of the inheritance of the 

 characters discussed, in the several varieties: 



Ben Davis does not carry yellow; in transmitting shape it is 

 less prepotent than either Green Newtown or Jonathan; as a 

 rule its crosses are intermediate in size; sweetness is carried 

 as a recessive. 



Esopus probably carries yellow skin color; shape is intermed- 

 iate in its progeny; the variable size of its progeny indicates that 

 at least one of its recent ancestors was sm^all; sweetness is car- 

 ried as a recessive. 



