61 



Another interesting example of color character consisting of more than 

 one unit was discovered in connection with a crossing between the white- 

 kernelled wheat sort Pudel (See Fig. 12) and 0700, a pedigree sort out of the 

 common red-kernelled Swedish Velvet chaff (44, p. 268). The kernels in F^ 

 of this crossing are Red, as Red is dominant over White; in F 2 the ratio 63 

 Red: 1 White was produced. This fact, together with results obtained in 

 later generations indicates that three character pairs must have been con- 

 cerned in this crossing. It is therefore assumed that the Red Color character 

 possesses three units for Red which, with the corresponding absence of the 

 same units, constitute three character pairs as follows: 



Red White 



Crossings between sorts which are apparently identical in regard to the 



characters considered. 



Two Red-kernelled wheat sorts No. 0234 (pure line from a Squarehead 

 variety) and 0406 (Svalof 's Bore wheat) , which are very similar in respect of 

 color of kernel, were crossed at Svalof in 1907 (54, p. 66). Fj was red 

 kernelled, while F 2 gave 52 red kernelled and 5 white kernelled individuals = 

 10.4 Red: 1 white. All the 57 F 2 individuals were sown out in separate 

 cultures and gave the following results : 



25 constant Red. 



13 segregating in the proportion 15 Red: 1 White. 



14 " 3 Red: 1 White. 

 5 constant White. 



Total 57 



These results indicate that each of the parents has its own peculiar unit 

 for Red Color. These two units with their corresponding absence in the 

 opposite parent, constitute two character pairs. The crossing may therefore 

 be expressed as follows : 



0406 

 (Red) 



I X I 



r 2 R 2 



According to the above scheme one of the combinations in F 2 will lack 

 both color units = (r 1; r 2 ) and consequently will be white-kernelled. 



