200 Certain Characters in the Cowpea (Vigna sinensis) 



The F^. 



1. Black bred true in 17 families containing 480 plants. 



2. In 51 families black segregated into black and New Era in the 

 3:1 ratio. 



Plants Black New Era 



1648 1244 404 



Expected ... 1236 412 



Ratio ... 3-1 : 10 



3. New Era bred true in 38 families containing 1363 plants. 

 From the results of these experiments it may be concluded that: 

 (a) B and E are not inherited independently. 



(6) B and E behave as though they were allelomorphic to each 

 other, but it need only be assumed at present that these two factors 

 show repulsion probably on a basis higher than 1 : 15. 



(/) The cross Para (albino) by Black-eye. 



. This experiment was designed to show whether either or both ot 

 the two pattern factors D and H are present in Para. Since the seed 

 coat of Para is unpigmented no pattern factor will have visible expres- 

 sion. 



The F^. Black solid. 



The Fz. Segregation took place in the coloured types into Solid, 

 Watson, Holstein, and Small-eye in approximately the 9:3:3:1 ratio, 

 thus: 



Solid Watson Holstein Small-eye 



Expected 



It is clear that Para contains both D and H. These factors have no 

 visible expression except in presence of the pigment factor R, brought 

 in by the black parent, 



3. Pod Colour. 



In certain varieties of cowpea the pod is green in the early stages 

 but shortly before maturity it develops anthocyanin pigment through- 

 out, turning through various shades of colour until when almost ripe it 

 is of a deep purplish-red colour. In purple podded plants there is also 

 colouration of the tip of the young pod, calyx, and peduncle, similar to 

 that caused by the factors B (black), and E (New Era). 



