No. 537] INHERITANCE OF THE "EYE" IN VIGNA 521 



These formulae give the ratios previously assumed in 

 dealing with our statistical data for the F 2 generation, 

 provided we assume W and H dominant respectively to 

 w and h. 4 An interesting deduction from them is that the 

 cross between the Watson and the Holstein types should 

 give the same ratio in F 2 , namely, 9:3:1:2:1, that the 

 cross between solid color and small eye gave. In the 

 original crosses, the cross ITolsteinX Watson was not in- 

 cluded, but it is included in crossings now being made. 



These formulas give some hint as to the nature of the 

 effect produced by the factors W and H. Comparing (4) 

 and (3), the factor H has the effect of enlarging the pig- 

 mented area from the small eye type to the Holstein type 

 (see b and e, Fig. 1). Comparing (2) and (4), W is seen 

 to have the effect of enlarging the pigmented area of the 

 Small Eye type, changing it to the Watson type (see g, 

 Fig. 1). W and H together, even in the hybrid WwHh, 

 have the effect of spreading pigment over the whole seed- 

 coat. 



We have seen that the heterozygote between Holstein 

 and Small Eye, which has the formula wwlfh, is inter- 

 mediate between the parent forms. In earlier pages this 

 type has been designated Large Eye. It therefore ap- 

 pears that H duplex enlarges the pigment area about 

 twice as much as H simplex does. Whether the same is 

 true of the factor W has not yet been determined. As the 

 ratio 9 :3 :1 :2 :1 is somewhat unusual, it may not be out 

 of place to illustrate the manner of its occurrence. In 

 the cross: Small EyeX Solid Color, F, has the formula 

 WwHh, and is solid color. Generation F 2 is as follows: 



