BIOLOGY IN HUMAN AFFAIRS 



had been able to produce. His inbred strains were collected 

 from several places; some he had produced himself. They 

 had all been tested in various combinations. The nubbins 

 that he pictured on the front page of his magazine had been 

 grown on inbred plants and were consequently poor, but 

 in each kernel there was a hybrid union of different heredi- 

 ties, purified by inbreeding. Each by itself was weak, but 

 in combination, powerful. 



In every district in Iowa — the United States Depart- 

 ment of Agriculture has made careful yield tests — this 

 crossed corn has given more bushels of good sound grain 

 than the best of the varieties previously grown. Similar 

 reports are coming from other states. Canners and market 

 gardeners are finding that the same method applied to 

 sweet corn gives astonishing results. The evenness in size 

 and shape of ear and the ability to ripen at the same time 

 are of even greater importance for sweet corn than for 

 field corn. 



Seed growers are taking an active interest in this new 

 method, and fields used for the production of crossed corn 

 seed are being planted with the two inbred types to be 

 crossed in alternating rows. In midsummer, as soon as 

 the tassels appear and before any pollen is shed, crews 

 of tassel pullers go into the field and jerk out the opening 

 panicle at the top of the plant from those rows that are 

 to supply the seed. The ears on these detasseled plants 

 receive their pollen from the adjacent rows, planted solely 

 for the purpose of supplying pollen. This crossed seed is 

 used only once. Later generations fall off in vigor and 

 yield. The extra vigor and production in the first hybrid 

 generation more than pay for the additional expense of 

 producing seed in this new way. 



In all the years that he has been growing plants and 

 feeding farm animals, the farmer, faced with the necessity 

 of making a living from the soil, has never carried his few 



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