442 GENETICS IN RELATION TO AGRICULTURE 



the utilization of superior locally adapted varieties or strains will become 

 correspondingly important. 



More comprehensive study of all the factors involved in a plant breed- 

 ing problem will be demanded of future plant breeders. Not only must 

 the inheritance of the economic characters of each crop plant be deter- 

 mined, but also the important desiderata of correlation between these 

 characters as derived from biometrical studies such as Harris' on the 

 physiology of seed production will need to be considered. Variety and 

 strain tests must become more comprehensive and at the same time more 

 specific as regards standards of selection. The data on disease resistance 

 especially should receive more particular attention. Finally the mathe- 

 matical adequacy of experimental data derived from breeding investi- 

 gations is a matter requiring the most serious consideration. 



The successful plant breeder will not only approach his problem from 

 a scientific point of view and with a knowledge of genetic principles; he 

 will be conversant with the developing requirements of 20th cen- 

 tury agriculture. If he would do his share in the creation of new and 

 more efficient types of crop plants, he must utilize the facts brought to 

 light by botanical, physiological, agronomic and horticultural investi- 

 gations. Of course there will always be the chance of accidental dis- 

 covery and the empiricist who operates on a large enough scale will 

 occasionally obtain valuable results. But the scientific plant breeder 

 of the future should combine the qualities of investigator and practical 

 agriculturist. The field is almost unlimited. During the 50 years 

 preceding the war plant breeding had increased the yields of crops in 

 Germany about 25 per cent. There were forty breeders of rye, seven- 

 teen breeders of potatoes, sixty of oats, and so on with the important 

 crop plants. When we consider the extent and diversity of agriculture 

 in America and the low average production per acre in most of our im- 

 portant crops, it is evident that the plant breeder has abundant oppor- 

 tunity. Yet it must always be remembered that the full possibilities 

 of applying genetics to breeding problems must await the gradual devel- 

 opment of scientific research. 



