212 BREEDING 



I have recognised all these nine zygotic types in 

 my own breeding experiments. 



It will be remembered that the cross which gave 

 this variety of forms was between a yellow wrinkled 

 and a green round. Two new types have arisen in 

 the second hybrid generation — the yellow round and 

 the green wrinkled. The latter may be counted upon 

 to, and actually does, breed true at once ; and it 

 only takes one generation longer to fix the yellow 

 round. All that is necessary, to do this, is to sow 

 the YE seeds, the cotyledons of which constitute 

 the second hybrid generation, so that the plants 

 raised have plenty of room, and then, when they are 

 ripe, to look for a plant all of the seeds of which are 

 yellow round. There should be one such plant 

 amongst every nine of the YR of the second hybrid 

 generation, and its seeds, when sown, will produce 

 nothing but yellow rounds. 



If, instead of crossing a yellow wrinkled with a 

 green round, a cross had been made between a yellow 

 round and a green wrinkled, the same series of forms 

 would have been produced in the second hybrid 

 generation, and in the same proportions ; but the 

 two new forms in it, in this case, would have been 

 the yellow wrinkled and the green round. The 

 isolation of both these forms in a pure state takes 

 the same time as that of the yellow round described 

 above. The yellow wrinkled seeds, the cotyledons 

 of which constitute the second hybrid generation, 

 are sown. All the seeds on the plants produced will 

 be wrinkled, but in two out of every three plants they 



