186 GENETICS 



3 red to 1 white when 1 heterozygous determiner for red 



is present. 



15 red to 1 white when 2 "1 heterozygous deter- 



63 red to 1 white when 3 > miners for red are 



All red to no white when 4 or more J present. 



Among seventy-eight sample families of the third 

 generation inbred to test this theoretical conclusion, 

 the actual results were: 



8 families giving the ratio of 3 red to 1 white. 

 15 families giving the ratio of 15 red to 1 white. 



5 families giving the ratio of 63 red to 1 white. 

 50 families giving the ratio of all red to no white. 



It has been actually demonstrated therefore, in the 

 case of this particular strain of wheat: (1) that the 

 factors producing red kernels are several in number; 

 (2) that they act independently of each other in 

 heredity; (3) that these several independent factors 

 segregate; and (4) that any one red factor acting 

 alone produces a "red" result. 



The Nilsson-Ehle principle of cumulative determiners 

 has been confirmed in America by East in a masterly 

 series of breeding experiments upon maize. 



In connection with the Nilsson-Ehle principle, it 

 will be seen that the possible number of intergrades 

 between the two extremes increases rapidly as the num- 

 ber of duplicate determiners increases. Thus with six 

 duplicate determiners for the same character present, 

 the ratio of possible dominants to recessives in the 

 second filial generation would be 4095 to 1. The re- 

 appearance of this single recessive among 4095 domi- 



