No. 597] INHERIT AXCE STUDIES IN PISU3I 



r>37 



519 seeds with yellow cotyledons were used to grow an 

 F 3 progeny. Of these, 166 F 2 seeds bred true or pro- 

 duced only seeds with yellow cotyledons, while 353 pro- 

 duced both yellows and greens in the proportion of 3 Y : 1 Gr. 

 353 to 166" gives a ratio of 2.13 to 1. Mendel (p. 327) 

 especially calls attention to the difficulties involved in 

 classifying the two colors of seeds, and notes, as I have 

 done in the preceding paragraphs, that the seeds of pure 

 green varieties and of segregate greens, have a tendency 

 to bleach, another fact that several critics of Mendelian 

 methods seem to have overlooked or forgotten. 



Mendel's work has been substantiated by a large num- 

 ber of trained investigators, as well as by a host of teach- 

 ers and amateurs. The results for cotyledon color in 

 Visum obtained by seven well-known geneticists are given 

 below (Table II). 



TABLE II 



These results approximate very closely the ratio of 

 3 Y : 1 G demanded by Mendel's theory. Darbishi ro (1913 

 p. 62) in testing out 140 F 2 progeny with yellow coty- 

 ledons, secured 98 F 3 plants heterozygous for given am 

 yellow cotyledons, and 42 breeding true or lionio/.ygou.. 

 for yellow cotyledons, a proportion of 2.3 heterozygous 

 F 2 plants to 1 homozygous F 2 yellow. Many yanotu- 

 gathered from all over the world were used m thes< 



