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. 
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