514 BIOLOGY AND HUMAN LIFE 



were practically lost to the world for fifty years. At the begin- 

 ning of the twentieth century several other scientists, working 

 independently, discovered the same principles, and later the 

 records of Mendel's experiments were found. These principles 

 serve as a basis for practical work of great value in the breeding 

 of plants and animals. 



375. Applied Mendelism. The region about Pullman, Wash- 

 ington, is one of the best wheat-growing countries in the world. 

 Here the farmers had for years tried out many varieties of 

 wheat in order to decide which was the most profitable to grow. 

 They found only the Little Club variety at all satisfactory, but 

 that also had its faults. The straw was strong enough to with- 

 stand the summer storms and the head remained closed after 

 the grain was ripe, thus preventing loss before harvesting ; but 

 when planted in the fall it would be frozen during severe winters 

 —once every three or four years. Although the farmers could 

 get better crops by planting in the fall, they could not afford to 

 lose every third or fourth planting. The problem was, there- 

 fore, to combine the good stem and head qualities of Little Club 

 with the frost-resisting qualities of some other variety. 



Mr. W. J. Spillman, at that time agriculturist of the experi- 

 ment station at Pullman, began a series of experiments in 

 crossing, or hybridizing, the Little Club wheat with other varie- 

 ties. He found that, whichever plant (variety) was used as the 

 pollen parent, the next generation always showed the same 

 group of characters. This is in accordance with what we have 

 learned as Mendel's law of dominance. He also found that in 

 the offspring of the hybrids every possible combination of the 

 grandparents' characters occurred. This is in accordance with 

 the law of segregation. 



By selecting individuals in this third generation and growing 

 from their seed, and by keeping careful and complete records of 

 the results, Mr. Spillman succeeded in finding the strains that 

 had the necessary elements in their germ cells and so trans- 

 mitted the desired combinations of characters, in accordance 

 with the law of combinations or the law of unit characters. In 



