192 GENETICS 



3 red to 1 white when 1 determiner for red is present. 



15 red to 1 white when 2 determiners for red are present. 



63 red to 1 white when 3 determiners for red are present. 



All red to no white when 4 or more determiners for red 



are 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 kernel 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 determin- 

 ers has been confirmed in America by East in a mas- 

 terly 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 

 number 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 reappearance of this single recessive among 4095 



