150 SYSTEMATIZED PLANT-BREEDING 



real concern is to obtain the greatest possible value 

 for his crop, and as our food supply is partially 

 dependent on this we may agree that his object is 

 a meritorious one. 



Plans were accordingly made to test the possi- 

 bility of using Mendel's principles to build up 

 fresh combinations of the somewhat elusive features 

 which go to the making of a wheat which the farmer 

 would consider good enough to displace the kinds 

 he already grows. These wheats have some excel- 

 lent features, the most prominent of which is that 

 if well cultivated they are capable of producing 

 very high yields of grain and straw per acre. On 

 discussing the possibility of improving wheats 

 with farmers it was found that they attached more 

 importance to this feature than to any other, and 

 without exception took the line that still heavier 

 yields per acre should be tried for. On the face of 

 it the solution of the problem seems impossible. 

 If one may assume that high and low cropping 

 capacity form a pair of Mendelian characteristics 

 then the expectation would be that a cross between 

 two varieties showing these characteristics would 

 ultimately produce new types with the yielding 

 capacity of one or other of the parents. But 

 more than one indirect line of attack was open. 

 The yield per acre is dependent on several distinct 

 factors, the most important of which, since they 

 are more or less controllable, are the supply of 

 food materials available for the growing plant and 



