438 



The Journal of Heredity 



seeds. This color seems to 

 arise from discoloration of the 

 seed by contact with the black 

 glume. Red Amber sorgo has 

 seeds which are uniformly red- 

 brown and this is dominant 

 over the feterita seed color. 

 The Fi seeds are all red-brown 

 like those of the Red Amber 

 sorgo ( Fig. 5 ). On the F.. plants 

 the segregation indicates that 

 two independent unit factors 

 are involved in the determin- 

 ation of the seed color. These 

 two factors may be designated 

 R (red) and B (brown). 



The suggested formula for 

 the two parents of the cross 

 are, for feterita rrbb and for 

 Red Amber sorgo RRBB. 

 Fi would therefore be RrBb 

 with red-brown seed like those 

 of Red Amber and F^ would 

 segregate into 9R-B- with 

 red-brown seed like the Red 

 Amber sorgo; 3 R-bb, plants 

 with seed having only the 

 red color; 3 riB-, plants with 

 seed having only the brown 

 color on a white background; 

 and 1 rrbb, plants with white 

 seed like feterita. 



The progenies of several 

 crosses l)etween feterita and 

 Red Amber sorgo which were 

 classified during the winter 

 of 1916-17 conformed cjuite 

 well with the two factor 

 lupothesis giving a good 9 : 3 

 : 3 : I ratio. The results of 



this classification are given in 

 One ot llu- plants used by tlu' wiilcis in the production of 'T-.l^l,^ \\' 

 new sorghums is feterita, of which a mature plant is shown n c / 4 i «-U 



above. From this picture, a clear idea of the leaf, stem, and Untortunatciy some Other 



head characters of this crop can be obtained; it should be progeny material of crosses 

 compared with the plant of Blackhull kafir, shown on the iK'tWeen these same varieties 

 opposite page, since the latter was the other parent of (classified later gave results 



ent paper. (Fig. 2.) ^/ ^ ' • ft' • 



*^ that are not m accord with 



the results in Table IV. There was a 

 3 : 1 ratio between red (red-brown and 

 red) and not red (brown and white), the 

 actual percentages being 75.9 per cent 

 to 24.1 percent. Separated, however, 

 on the basis of brown and not brown, 



A FETERITA PLANT 



many of the crosses discussed in the present paper. 



the real object to be kept in mind pre- 

 vented a more comprehensive genetic 

 survey of the very interesting and 

 abimdant material. Howe\er, the man- 

 ner in which se\eral minor characters 

 were inherited was determined. 



INIIKKITANrK OF SKKD COLOR 



Feterita X Red Amber Sor^o 

 The seed of feterita is blm'sh-white 

 with limited areas of brown on some 



there was an excess of brown actually 

 80.2 per cent of this class. The diffi- 

 culty seems to haAe been in the separa- 

 tion of the red-brown and reds, there 



