58 BREEDING 



hybrid generation produced by crossing, in 1910, 

 a tall with a dwarf pea. The only difference between 

 the two cases is that the character of the first hybrid 

 generation can be seen before the seed to produce 

 plants of the first hybrid generation is sown, in the 

 case of the colour of the cotyledons ; but cannot 

 be seen until after the plants of the first hybrid 

 generation have grown a few inches, in the case 

 of the stature of the plant. 



It will be remembered that the colour of the first 

 two " leaves," or cotyledons, of the plants of the 

 first hybrid generation could be seen in the pods of 

 one of the parent plants in the same year in which 

 the cross was made. Similarly, the colours of the 

 cotyledons of the plants of the second hybrid 

 generation can be seen in the pods borne by the 

 plants of the first hybrid generation ; that is to say, 

 in the case of the cross made in 1910, in the 

 autumn of 1911. 



In Plate I. are shown the results of crossing a 

 green-seeded with a yellow-seeded pea, as far as the 

 second hybrid generation which we are now con- 

 sidering. Above, to the left, are seen a group of 

 ten peas, the cotyledons in which are green ; on the 

 right a group of six peas containing yellow cotyledons. 

 The skin of the vividly yellow pea to the top left 

 of this group has been removed in order to show 

 the colour of the cotyledons themselves. These two 

 groups represent the parents of the cross. The 

 group of three yellow peas in the middle, below, 

 contain the cotyledons of the first hybrid generation. 



