A still more remarkable case was observed 

 in crosses between varieties of wheat of dif- 

 ferent grain-color. Red crossed with white 

 gave ordinarily all red in F a and 3 red to 1 

 white in F 2 , but a certain native Swedish sort 

 gave only red (several hundred seeds) in F 2 . 

 This result was so surprising that one cross 

 which had yielded 78 grains of wheat in F 2 was 

 followed into F 3 , with the following result: 



50 plants gave only red seed; expected 37 



5 " " approximately 63 R: 1 W; " 8 



15 " 15R:1W; " 12 



8 " " 3R:1W; " 6 



" all white; " 1 



The interpretation given by Nilsson-Ehle is 

 this. The red variety used in this cross bears 

 three independent factors, each of which by 

 itself is able to produce the red character. 

 Their joint action is not different in kind from 

 their action separately, though possibly quanti- 

 tatively greater. The F 2 generation should 

 contain 1 white seed in 64. It happens that 

 none were obtained in this generation. The 

 next generation should contain in a total of 

 64 individuals, the sorts actually observed as 



132 



