T^Kw York AciRicuLTURAL Experiment Station. 475 



shape, may be either composed of many factors or it may be in- 

 herited as an intermediate condition — a question, of course, 

 still open for experimental evidence. 



INHERITANCE IN THE SEVERAL VARIETIES. 



The results of the study of Mendelian inheritance in this ex- 

 periment may be put in more workable shape for the apple- 

 breeder if the discussion of the several characters are summarized 

 under the varieties crossed. At the risk of considerable repeti- 

 tion, such a summary is now given. 



Ben Davis. — In the six crosses in which this apple was used, 

 the results indicate that yellow is not carried by Ben Davis — 

 the heterozygous R y progeny being able to obtain their yellow 

 from the other parent in each case. In transmitting shape, Ben 

 Davis was less prepotent than either Jonathan or Green New- 

 town. In the other cases, the individuals showing preponder- 

 ance of Ben Davis shape were about equal in number to those 

 showing the shape of the other parent. The term prepotent 

 is here used to mean that either the shape-forming characters 

 of one variety are less heterozygous than those of another, or, 

 that such characters of one parent are dominant over those of 

 the other. The greater the number of heterozygous characters, the 

 greater the number of segregations or splittings that will take 

 place. In size of fruit, the Ben Davis crosses were inter- 

 mediate as a rule, although the cross with the Green Newtown 

 produced offspring larger than either parent and none smaller. 

 Sweetness appeared as a recessive in all Ben Davis crosses except 

 with Esopus and here the four individuals are too few to permit 

 conclusions. 



Esopus. — The crosses between Ben Davis and Esopus are the 

 only ones with sufficient numbers to warrant a postulation as to 

 the gametic constitution of the Esopus color factors. The total 

 individuals obtained are 21 pure reds and 12 individuals 

 heterozygous for red and yellow. As the Ben Davis probably 

 does not carry yellow, the yellow in these heterozygotes must have 

 come from Esopus. Assuming that Ben Davis carries R II and 

 Esopus R y we should expect a ratio of 1 R R to 1 R y. 

 The ratio obtained, 7 :4, indicates that red is not carried in such 



