New York Ageicultural Experiment Station. 849 



We know, as jet, almost nothing of the unit characters in apples, 

 and the way they are inherited, and until this foundation knowl- 

 edge is secured it will be difficult to select, with any degree of cer- 

 tainty, the parents whose progeny will combine the qualities we 

 desire in our new variety. 



The determination of the factors by which the various charac- 

 ters are transmitted will be no easy task ; for work in other fields 

 proves that many characters depend not on one factor alone, but 

 on several that may be separately inherited, and the experiments 

 here recorded imdacate that this is markedly true of the apple. 

 Shape, size and color of fruit may depend upon the presence or 

 absence of several factors. Some factors or characters may not 

 appear at all in the first generation, and this skipping of a gen- 

 eration may complicate matters and involve a second crossing and 

 wait of ten or twelve years before we secure the combination the 

 parent characters led us to expect. To secure all the possible 

 combinations from any cross we must have large numbers of 

 plants, which is difficult and time-taking with apples. 



There is liability also, in selecting parents, of mistaking qual- 

 ities due to environment rather than to the constitution of the 

 plants themselves ; for these qualities, as acquired characters, are 

 not inherited ; though the advocates of " pedigreed stock " would 

 lead us to suppose that they are. 



In some cases, also, characters do not act as Mendelian pairs ; 

 but blend rather than segregate in crossing, so that the seedlings 

 may, in some desired respect, be intermediate between the parents, 

 giving no combination containing the one specially good quality 

 we wish. 



These and other difficulties confront the apple breeder ; but the 

 importance of the fruit, and the help we have in Mendel's laws, 

 making breeding a problem and not a riddle, certainly justifies 

 much careful, continuous work with this queen of American 

 fruits. 



