198 Certam Characters in the Coivpea (Vigna sinensis) 



Significance of the Mottling. 



It was pointed out above that some of the F^ seeds showed a certain 

 degree of mottling, and that the buff groundwork was visible in patches 

 in these seeds. In the F2 blacks, some of the plants showed no mottling 

 at all, whilst of the others some showed red and others buff mottling. 

 Eighteen blacks with no mottling were grown in F^, and all bred true 

 to black. Fifteen red-mottled blacks were grown in F^, and all except 

 one segregated into black and red. Many of the blacks were mottled 

 red. Forty-one families were grown from buff mottled blacks. Of 

 these sixteen segregated into black and buff, and twenty-two into black, 

 buff, and red. ' Three bred true. It may be concluded that mottling 

 indicates that factor B is present in a heterozygous condition, but that 

 some plants showing slightly mottled seeds may be pure for this factor. 



{d) The cross New Era by White. 



New Era is one of the best known varieties of cowpea, being highly 

 valued by the farmers of the Southern States as a forage crop. The 

 seeds are thickly and uniformly dotted with a dark blue anthocyanin 

 pigment, on a buff background. The New Era pattern is always 

 associated with purple colouration of the tip of the young pod, calyx, 

 and peduncle. 



The ^1 of the cross between New Era and the white variety Para 

 had seeds with the characteristic New Era pattern but with a less 

 intense dotting. In F2, segregation occurred into New Era, buff, and 

 white approximately in the 9:3:4 ratio. 



In Fs three families were grown. One of these was from a white 

 and bred true (23 plants). The other two were from plants of the New 

 Era type ; both segregated into New Era, buff, and white in the 9:3:4 

 ratio, as follows : 



Plants New Era Buff White 



30 14 6 10 



24 11 4 9 



Totals ... 54 25 10 19 



Expected... — 30 10 14 



Interpretation of the results of the cross New Era by White. 



The results obtained in the cross New Era by white indicate that 

 two factors are involved : 

 R the factor for red. 



