28 BREEDING 



I have shown the peas in the pods, in order to 

 emphasise the fact that all the seed-coats on a plant 

 are the same — all grey on the plant in Fig. 11, 

 and all white on the plant in Fig. 12. This is a 

 very important point to bear in mind. 



The hybrid produced by crossing a white -skinned 

 pea with a grey-skinned one was found by Mendel 

 to be grey. The second hybrid generation consisted 

 of 705 grey-skinned plants, and 224 white-skinned 

 ones. A hundred of the former were tested, and 

 thirty-six gave grey-skinned ones only ; the remain- 

 ing sixty-four gave both grey-skinned and white- 

 skinned plants. 



Let us now take a retrospective glance at the 

 five characters of the pea, the manner of inherit- 

 ance of which has just been described. 



Let them be considered first from the point of 

 view of the time at which they appear in the life- 

 history of the plant. The difference between tall 

 and dwarf appears in the very young seedling long 

 before it needs to be supported with a stick. The 

 difference between normal and fasciated cannot be 

 detected until the plant has grown to some height 

 and needs the support of a stick ; but it can be seen 

 before the appearance of the flower buds. The 

 difference between hard and soft pods cannot, of 

 course, be detected until after the flower is " over " 

 and the pod has begun to develop, but it can be seen 

 very soon after the pod projects beyond the withered 

 petals, and long before the peas begin to fill out the 



