IMPROVING FARM CROPS 23 



25.20 pounds of butter in seven days. In the center is her 

 daughter who produced 26.90 pounds in seven days. On 

 the right her granddaughter who produced 30.03 pounds. 



The trotting horse called Messenger was not famous 

 for his speed, but nearly every one of the best trotting 

 horses of today has some of his blood. 



Not every attractive plant or animal is desirable. 

 Much too often an attractive young male is placed at 

 the head of a herd, only to find that a mistake has been 

 made. Whenever possible, it is desirable that individu- 

 als be selected because they have good offspring. 



IMPROVING SOME FARM CROPS 



23. Plant-Breeding vs. Animal-Breeding. The plant- 

 breeder has several advantages over the animal-breeder: 



(1) He can grow large numbers at small cost, and so 

 have greater numbers to select from. He need save only 

 one in thousands. The animal-breeder must work with 

 fewer numbers, and save a larger proportion. 



(2) When superior plants are obtained, they can be 

 rapidly multiplied. 



(3) Many plants can be propagated by asexual means, 

 hence avoiding the reversion that comes from seeds. If 

 a desirable hybrid is found, it is not given a chance to 

 revert, but is propagated by buds, roots, or cuttings. 

 Our varieties of apples, strawberries, and most other fruits, 

 potatoes, and many flowers, would be lost if they had to 

 be propagated by seeds. 



24. Comparative Improvement of Different Crops. Those 

 crops in which the individual has been handled by the 



