204 Certain Characters in the Cowpea (Vigna sinensis) 



Interpretation of the Results. 



The evidence, although incomplete, indicates that the tinged type 

 of flower is due to a factor which may be called G. This factor is 

 recessive to D, the factor for dark flower, and tinged and white form a 

 pair of allelomorphic characters. 



It was thought at first that the cross was of the nature DGR x Dgr 

 giving in F2 : 



9 DGR 3DgR 3dGr 1 dgr 



Dark Dark Tinged White 



or altogether 12 dark, 3 tinged, and 1 white. According to this hypo- 

 thesis the number of darks segregating into dark and tinged, and dark 

 and white respectively in F^ should be equal in number. Actually no 

 darks segregated into dark and white, whereas 7 segregated into dark 

 and tinged. The F^ families which segregate into all three types should 

 exhibit the 12:3:1 ratio. The actual figures show considerable deficiency 

 in the number of whites. It may be noted that it is not easy to dis- 

 tinguish between tinged and white in some plants, and possibly some 

 plants have been classified as tinged which are really white. 



On the whole the evidence is in favour of the view that the cross is 

 DGR by Dgp, but a much larger series of numbers is necessary to sub- 

 stantiate the theory. 



The two factors D and L have no visible effect except in presence of 

 the factor R (red). The factor G produces the tinged type of flower in 

 plants with white seeds. 



General Summary. 



« 1. The presence of anthocyanin colouration in stem and leaf stalk is 

 due to a factor X, dominant to its absence. 



2. The colours of the seed coat pattern, black, brown, buff, maroon, 

 red and white may be regarded as due to various combinations of four 

 factors, B (black), N (buff), M (maroon), and R (red), thus : 



