EXPERIMENTS IN PLANT HYBRIDISATION. 



19 



first trial 90 plants, and for the third 87 plants which fruited : these 

 yielded for the — 



1st 3rd 



Experiment Experiment 



20 25 round yellow seeds . . • • AB. 



23 19 round yellow and green seeds . • , ABb. 



25 22 round and angular yellow seeds . . AaB. 



22 21 round and angular green and yellow seeds AaBb. 



In the second and fourth trials the round and yellow seeds yielded 

 plants with round and angular yellow and green seeds, AaBb. 



From the round green seeds plants resulted with round and angular 

 green seeds, Aab. 



The angular yellow seeds gave plants with angular yellow and green 

 seeds, aBb. 



From the angular green seeds plants were raised which yielded again 

 only angular green seeds, ab. 



Although in these two trials likewise some seeds did not germinate, 

 the figures arrived at already in the previous year were not aftected 

 thereby, since each kind of seed gave plants which, as regards their 

 seed, were like each other and different from the others. There resulted 

 therefore from the 



2nd Experiment 4th Experiment 



31 24 plants of the form AaBb 



26 25 „ „ Aab. 



27 22 „ „ aBb. 

 26 27 „ „ ab. 



In all the trials, therefore, there appeared all the forms which the 

 proposed theory demands, and also in nearly equal numbers. 



In a further trial the characters of floral colour and length of stem were 

 experimented upon, and selection so made that in the third trial-year each 

 character ought to appear in half of all the plants if the above theory 

 were correct. A, B, a, b serve again as indicating the various characters. 



A, violet-red flowers. a, w^hite flowers. 



B, axis long. b, axis short. 



The form Ab was fertilised with ab, which produced the hybrid Aab. 

 Furthermore, aB w^as also fertilised with ab, whence the hybrid aBb. In 

 the second year, for further fertilisation, the hybrid Aab was used as 

 seed parent, and hybrid aBb as pollen parent. 



Seed parent, Aab. Pollen parent, aBb. 



Possible egg cells, Abab. Pollen cells, aBab. 



From the fertilisation between the possible egg and pollen cells four 

 combinations should result, viz. : — 



AaBb + aBb + Aab -f ab. 



From this it is perceived that, according to the above theory, in the 

 third trial-year out of all the plants 



c2 



