MODERN PLANT-BREEDING METHODS: 



WITH ESPECIAL REFERENCE TO THE 

 IMPROVEMENT OF WHEAT AND BARLEY 



By R. H. BIFFEN, M.A. 



Agricultural Department, Cambridge University 



At the opening of the twentieth century the subject of breeding 

 had reached a critical stage in its development, and the few 

 years that have since passed have seen it placed upon a satis- 

 factory basis. In place of fantastic hypotheses the breeder now 

 possesses well-grounded facts on which it is possible to base 

 comprehensive plans for the betterment of the plants which are 

 the objects of his experiments. The main line of attack, until 

 recently, has been that known as " selection." For many years 

 the breeders have recognised the fact that the offspring of a 

 given individual differ amongst themselves to a certain extent, 

 and they have considered that if those individuals showing — 

 from their point of view — the most favourable variations were 

 selected, further generations raised from them, and this process 

 of selection repeated year by year, it was possible to effect 

 vast improvements. Many examples might be quoted of 

 attempts made by breeders to sum up these small differences. 

 So simple was the process that the breeder hardly appeared to 

 recognise its possible limitations, and so readily understandable 

 was it that no seedsman could afford to be without his " pedigree 

 cultures." If this process of selection was indeed capable of 

 one-half that its advocates imagine, then it is incredible that so 

 little progress has been made with plant improvement. By now 

 we might fairly have expected the demands in many directions 

 to have been met : a hardy marrowfat pea, for instance, should 

 not still be wanted, or yet a potato which a late May frost would 

 not spoil. There are many such desiderata which selection has 

 brought no nearer to us. 



At this time the diverse phenomena grouped together under 

 the term "variation" were beginning to be analysed in detail, 



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