3i6 PLANT HYBRIDIZATION BEFORE MENDEL 



No. of seeds Composition Formula 



Series I yielded 20 round yellow AABB 



23 round yellow (green) AABb 



25 round (wrinkled) yellow AaBB 



22 round (wrinkled) yellow (green) AaBb 



Series III yielded 25 round yellow AABB 



19 round yellow (green) AABb 



22 round (wrinkled) yellow AaBB 



21 round (wrinkled) yellow (green) AaBb 



This means that, when all of the 90 plants in Series I ran to 

 seed, 20 of them yielded all round yellow seeds ; 23 plants yielded 

 yellow and green seeds in a ratio of 3 : 1, and thereby showed that, 

 although looking round yellow^ their actual composition was 

 round yellow {green) AABb. Likewise, there were 25 that yielded 

 round yellow and zorinkled yellow in the ratio of 3:1, thereby 

 proving that their original composition, although they also all 

 looked round yellow^ was actually round {wrinkled) yellow., 

 AaBB. The same hybrid condition {for both character-pairs) was 

 also shown to exist for the 22 seeds of the 90 plants in Series I, 

 which split up into plants bearing partly wrinkled and green 

 seeds as recessives, thus revealing the original composition of 

 these 22 seeds sown to be AaBb. 



The analysis having been made clear for Series I and III, let 

 us turn back to Series II and IV, and see what their actual com- 

 position turned out to be. Mendel found as follows : 



SERIES II 



The 31 round yellow seeds yielded plants with round (wrinkled) yellow 



(green) seeds — AaBb 

 The 26 round green seeds yielded plants with round (wrinkled) green 



seeds — Aabb 

 The 27 wrinkled yellow seeds yielded plants with wrinkled yellow 



(green) seeds — aaBb 

 The 26 wrinkled green seeds yielded plants with wrinkled green seeds 



— aabb 



SERIES IV 



The 24 round yellow seeds yielded plants with round (wrinkled) yellow 



(green) seeds — AaBb 

 The 25 round green seeds yielded plants with round (wrinkled) green 



seeds — Aabb 

 The 22 wrinkled yellow seeds yielded plants with wrinkled yellow (green) 



seeds — aaBb 

 The 27 wrinkled green seeds yielded plants with wrinkled green seeds 



— aabb 



