14 BREEDING 



grains are transferred from the flowers of a tall 

 plant to a particular part of the female organ of a 

 dwarf plant, or vice versa. The details of this 

 process will be described in Chapter X. The main 

 point which I wish to be noted here is that the 

 pea is always self-fertilised unless it is artificially 

 cross-fertilised by the agency of man. 



We have seen that dwarf plants, when left to 

 themselves, set seed which produces dwarf plants 

 only ; and that tails similarly breed true. 



We will now consider the result of crossing a tall 

 with a dwarf. 



The plants which result from a cross between a 

 tall and a dwarf are always tall. These tails are no 

 shorter than their pure tall parents ; in fact, as a 

 rule, they are a little taller, because, like most hybrids, 

 they are very vigorous. They constitute the first 

 hybrid generation. 



These hybrid tails are allowed to self-fertilise. If 

 the seed saved from them is sown, about three- 

 quarters of the plants produced are tall, and about 

 a quarter are dwarf. That is to say, in every four 

 plants, three are tall and one is dwarf, on the average. 

 This average result is shown in the genealogical 

 table which forms the frontispiece, where it will also 

 be seen that this generation — namely, the one which 

 consists of three tails and one dwarf in every four — 

 is called the second hybrid generation. 



Let us now consider the result of sowing the seed 

 saved from the plants composing the second hybrid 

 generation. These plants, like those of the first 



