70 



BREEDING 



diminish as the generation in question becomes more 

 remote from the green parent of the cross. In other 

 words, it is a remarkable thing that a yellow of the 

 tenth hybrid generation, with nine generations consist- 

 ing solely of yellows behind it, should contain as 

 many greens as the second hybrid generation, which 

 has only one such generation behind it. There is no 

 possibility, here, of eradicating the green by breeding 

 only from the yellow ; unless pure yellows are bred 

 from. The evidence, as yet available, as to the ratios 

 of recessives, in the case both of cotyledon colour 

 and shape, has been collected by Mr. Lock in his 

 useful paper, " The Present State of Knowledge of 

 Heredity in P^'swm,"* and is as follows. The name 

 of the investigator is given in the case of each separ- 

 ate result : — 



* Annals of the Royal Botanic Gardens, Peradeniya, Vol. IV., Pt. iii. 



