196 



Plant-Breeding 



type was present in a certain proportion, which was ap- 

 proximately the same as in thirteen other similar cases, 

 and the average of these fourteen cases approximated the 

 theoretical numbers called for by Mendel's hypothesis 

 of the disjunction of parental characters. The three 

 at the left, being bearded, possess a character which 

 was latent in the first generation. The fact that the 

 beards show in these three indicates that the opposite 

 character is absent, and they should therefore remain 

 bearded in succeeding generations. That is, they are no 

 longer hybrid with reference to this character. It will 

 be observed that this was actually the case, for no beard- 

 less heads appeared in the progeny of either of these three 

 (see lower row, first five heads). The following diagram 

 will show the character of each of the six types in row 2. 

 In this diagram the letters have the following meanings : 



B = bearded (written b when latent) . 

 S = smooth (not bearded). 

 L = long heads. 

 C = Club heads (short). 



I = Intermediate in length of head. (The hybrid was 

 intermediate in this respect.) 



PARENTS FIRST GENERATION 



SECOND GENERATION 



BL 



SC, 



Sbl 



BL 

 BI 

 BC 



SbL 



Sbl 



2 SbC 



1 SL 



2 SI 



16 



