532 



WHITE— STUDIES OF INHERITANCE IN PISUM. 



proximately 3 round smooth : i wrinkled. There is no case of 

 coupling known between these two cotyledon characters and flowe 

 color, so the ratio is 3 : i whether the flowers are white or colored. 

 In F3 about one third of the round seeds produce only plants having 

 round seeds, while two thirds of the round seeds again produce 

 plants which have round seeds and wrinkled seeds in the proportion 

 of 3: I. The wrinkled seeds always breed true. The results from 

 crossing round smooth and wrinkled seeded varieties as obtained by 

 five well-known geneticists are : 



gave: 



Back-crossing heterozygote F^ with pure round smooth parent 



Mendel 192 



Tschermak 38 



Back-crossing heterozygote F^ with pure wrinkled seeded parent 

 gave rovmd smooth and wrinklcds in the ratio of 1:1 or 



Round. 



Mendel 106 



Tschermak 26 



132 



Wrinkled. 

 102 

 18 

 120 



No coupling or " correlation " of other common characters such 

 as tallness, flower color, cotyledon color, fasciation and pod color 

 with wrinkledness have been recorded. Partial coupling between 

 wrinkledness and lack of tendrils ("acacia") has been studied by 

 Vilmorin (88, 89), Bateson (88) and Pellew (64). This will be 

 discussed in connection with foliage characters. 



