HYBRIDISATION AND SELECTION. 73 



Other, but all the seeds of the same cross do it in 

 the same way. 



On then sowing the seeds of the plants pro- 

 duced from this first cross, variations begin to 

 appear. Most of the progeny revert to one or 

 other of the parent forms, others show all con- 

 ceivable combinations of their characters, and a 

 few may give rise to entirely new characters. In 

 succeeding generations the reversions are pre- 

 ponderant, and, supposing no care is taken to 

 prevent it, the whole of the offspring gradually 

 go back to the ancestral type. 



Some important consequences result, however, 

 if systematic care is brought to bear on the matter. 

 This tendency to variation in the second genera- 

 tion of crossed plants has often been noted, and it 

 bears out very distinctly the conclusions to which 

 Darwin came. 



The hybridiser takes advantage of this variation, 

 as others have done, to select some forms and 

 rigidly suppress others, in order to obtain well- 

 marked varieties of the plants he experiments 

 with. In illustration, I may take the following 

 from Rimpau's account of his experiments on 

 crossing wheat : By crossing a white English 

 long-eared, dense wheat, and celebrated as a 

 heavy cropper, with a red, looser German wheat, 

 remarkable for its resistance to winter cold, 

 Rimpau hoped to obtain a variety uniting both 

 the above qualities. As regards the property of 

 resistance, he failed, and he eventually gave up the 

 attempts in face of the advantages offered by the 



