Dec. 6, 191S Inheritance of Length of Pod in Certain Crosses 



419 



Table XI. 



'Comparison of the pod lengths of third-generation parents with those of 

 their long-podded progeny 



To sum up, the fourth-generation families show either that selection 

 for long pod had been efifective in isolating plants homozygous for 

 minor factors or that segregation of the residual minor factors was in 

 most cases masked by the modifications. 



SUMMARY 



(i) A single genetic difference, E, is responsible for the main differ- 

 ence between short and long pods. This genetic difference segregates 

 in normal Mendelian fashion. 



(2) Factor E is completely quantitatively dominant, so that E^ = Ee. 



(3) This factor acts as a multiplier, with a multiplying value of about 

 1.51. 



(4) Minor factors for pod length also act as multipliers, with a com- 

 bined multiplying value (when double) of about 1.42. 



(5) These minor factors apparently show zero dominance, in the sense 



that ii A2 B2 C2 are positive double factors with a combined 



multiplying value of x, the value of AaBbCc is -y/x. 



LITERATURE CITED 

 (i) Bateson, William. 



1909. Mendel's Principles of Heredity. 396 p., illus. Cambridge, [Eng.]. 

 Bibliography, p. 369-384; supplementary list, p. 385. 

 (2) Belung, John. 



1912. Second generation of the cross between Velvet and Lyon beans. In Fla. 

 Agr. Exp. Sta. Ann. Rpt. [igioj/ii, p. Ixxxii-civ, fig. 15-31. 



