A OENETICO-PHYSIOLOGICAL STIDY ()X THE FoRJ[ATION ETC. f)5 



With respect to the coloiu- of the gi-jiiu, let two piiirs of geues 0' o' iiud 

 C c' be responsible. The chroiuogeu C pixxluces the cluxjinogeiiic substauce 

 P in the testa and in pericarp, and c' produces practically uouo. The gene 

 0' converts the cliromogeiiic substance to a i-eddish bix)wu pigiueut especialh- 

 in the testa and o' to a less extent. Thus bj- CO' the reddish brown gi-aiu 

 is formed and by Go' the yellowish brown gi-ain. Tlio ]3arontal reddish brown- 

 gi-ain plant may he assumed to Ixi CO' aud the " white "-gi-aiu plant c'o'. 

 Tlie 9:3:4 ratio would arise in F, by selfiug the F^ plant Cc'O'o'. Thus 



GO' 9 Keddish brown 



Go' 3 Yellowish bro«n 



c'O' 3 "White" 



c'o' 1 



With respect to the colour of the jialeas, the segi'egation in F^ -was similar 

 to that of the cross " Hanbun-nento " x " Geuroku-moclii ", so we maj- assume 

 that the analogous genes are concerned in the cix^ss " Otsubu " x " Haguro " 

 in which the gi-ain colom-s ai-e studied. But one of the genes for the gi-ain 

 coloura pix)bablj- 0' is completely linked with the gene for the purple colour 

 of the palea. Suppose 0' is linked with P but C is independent of the 

 latter, we expect the following segi'egatiou in i^. . 



BPO'C 27 Awn pm-ple, palea self purple, gi-ain reddish brown. 



„ „ " white " 



„ localized pm-ple reddish brown. 



„ „ " wliite " 



brown brown yellow, brown. 



„ „ " wliite " 



„ yellow yellow, brown. 



" white " 



If reddish bivmiis, yellowish bl•ü^\■ns and " whites " ai'e added together iiTC- 

 spective of the colour of the paleas, we obtain 3G : 12 : 16 or 9:3:4 ratio. 

 The ratio of coloured to non coloui*ed grains in each colour tyjies of the paleas 

 is 3 : 1 showing tliat the gene C is indei^endeut of P' and 0'. 



As we have already seen, green and yellow seed coat of the soy l)eans 

 are dominant over bhick, brown and buil'. The gi-eeu and yellow contain 



