434: MIXPERIMENTS WITH PLANTS 



seed; for, aftei selection has achieved the ideal, it 

 has still the task of "fixing" it so that it will come 

 true to seed. 



Ill order to achieve our ideal, we have had to set 

 in motion the tendency to variation, or, as we say, we 

 have "broken the type.", When the ideal is achieved, 

 this same tendency which we have set in motion will 

 destroy our ideal unless selection is able to suppress 

 the tendency and so "fix the type," or, in other 

 words, bring the plant again to a state of equililjrium. 

 This we can do to a great extent, but not so full^y 

 that continued selection is unnecessary. And it often 

 happens that, after an ideal is achieved, years elapse 

 before it is sufficiently fixed to put it on the market. 



The great possibilities of selection ai-e well illus- 

 trated in the case of corn -breeding as carried on 

 by Professors Hopkins and Sham el at the IlUnois 

 Experiment Station.^ At the same time, these ex- 

 periments illustrate the great value of a thorough 

 acquaintance with the plant and its possibilities, com- 

 bined with a knowledge of the desirability of the 

 various possible lines of improvement as shown by 

 the demands of the market. Suppose you were to 

 undertake the production of an improved variety of 



'See "r.irii Culture and Breerling," Thirteenth Report Kansas Board of 

 Agriculture, XVIII, 78r)-817. Also Bulletin No. 82, Illinois Agricultural 

 Experiment Station, 525-539. Also articles hy Professor Shaniel in the 

 Coxmopolitan for May. 1903; by W. S Harwood in TTorM'.f Worl- 

 for Septenil)er, 1902, and l)y C. P. Hartley iu Year -Book of the United States 

 Department of xVgriculture tor 1902. 



