WHITE— STUDIES OF INHERITANCE IN PISUM. 



509 



F4 generation grown by Lock but actual figures not recorded. 



In addition to the figures given above are those from crosses 

 made by Correns, Tschermak and others. These data are omitted 

 here because either the exact figures are not given in the original 

 papers or that these figures are scattered through so many papers 

 and so often repeated as to make their accvtrate collection imprac- 

 ticable. 



In F3, a certain proportion of the Fo segregates with colored 

 seed coats breed true, another portion break up, giving again the 

 3 : 1 ratio, while the Fo segregates with colorless seed coats breed 

 true. 



In certain crosses made by Tschermak (86) between colorless 

 and gray brown (whitish brown) seed coat varieties, F^ progeny 

 with dark brown seed coats were obtained, which in F^ gave dark 

 browns, grays and colorless seed coat segregates, approximating the 

 proportion 9:3:4. 



Colorless X gray seed coat with purple dots gives in the next 

 (Fj) generation, all gray purple dotted seed coats. In Fo, the fol- 

 lowing results have been obtained : 



Fo heterozygotes in Fg gave : 



In F^, Lock (55) tested out the genetic nature of non-purple 

 dotted colorless seed coat F., segregates which had bred true in F^ 



