,6, I9I5 Inheritance of Length of Pod in Certain Crosses 



411 



young pods except eight were removed from a plant of the Florida velvet 

 bean the length of 5 -seeded pods increased from 63 to 73 mm. The 

 plants in 191 2 were grown in an especially favorable season, and more 

 of the late plants had time to ripen their pods than in 19 10. 



Table V. — Frequency arrays of the average lengths of ripe ^-seeded pods of bean plants 

 tvith white shoots of second generations of the reciprocal crosses (classes of j mm.) 



FLORIDA VELVET BEAN X LYON BEAN, IQIO 



LYON BEAN X FLORIDA VELVET BEAN, 1912 



'■ Black plant. 



The actual averages ' were : 



1910. 

 1912. 



These are sensibly the same as the most trustworthy averages (62.8 

 and 94.5 mm.) for the Florida velvet bean and the I^yon bean in 1912. 



The average of the first-generation plants is probably near 95 mm. 

 The average of the long-podded plants of the second generation is 94.7 

 mm. Therefore, the factor E is probably completely dominant. 



Thus, in the second generation the short pods and the long pods give 

 the grandparental averages. The minor factors affecting pod length 

 have not perceptibly altered the averages by their segregation, which 

 agrees with the conclusion that E was completely dominant and the 

 minor factors showed zero dominance and acted symmetrically with 

 regard to both long and short pod, decreasing and increasing to the same 

 extent each parental pod length. Calculation shows in this case that the 

 increase of the second-generation averages over the parental lengths, 

 which is a consequence of the hypothesis that the factors act as multi- 

 pliers, is so small as to be negligible. 



' The averages have been calculated from the actual figures, not from the frequency classes. 



