IMPROVEMENT OF FIELD CROPS 23 



common expression that this animal is a good breeder or that 

 animal a poor breeder. 



At the Ohio State University in 1902, fourteen ears of maize 

 of a given variety were selected, and two rows of fifty hills each 

 were planted from each ear. The smallest ear, containing next 

 to the smallest weight of maize, produced the heaviest yield of 

 maize. This ear weighed 14 per cent less than the average 

 weight of the fourteen ears and yielded 32 per cent more than 

 the average yield of the same fourteen ears. This testing of 

 the power of plants to transmit their characteristics is pains- 

 taking work, and will form a large part of the work of the 

 successful plant breeder. 



45. Importance of Large Numbers, — If a thousand persons 

 stand in a row it will be found that most of them are nearly the 

 height of the average, while a few are considerably shorter and 

 a few considerably taller than the average. The length or 

 weight of a number of ears of maize will vary in the same 

 manner as shown in wheat. (42) In fact this seems to be a 

 universal law of organic beings. Most of them tend to breed 

 true to type : a few vary considerably from the t}'pe. In order, 

 therefore, to make progress in breeding it is necessary to find 

 the organisms that have the tendency to vary as desired. Among 

 a million organisms there may be only one that possesses the 

 required characteristics. The chances of finding the desired 

 individual increase as we increase the number from which selec- 

 tion is made. The chances of securing satisfactoiy results are 

 increased many fold if 5000 seeds are planted instead of 500. 



46. The Plant Breeder's Advantage. — It has been sho\\Ti 

 that the breeder of animals has the advantage of the breeder of 

 plants in that he can more easily control the mating of the 

 parents. The breeder of plants has a distinct advantage in 

 being able to work with large numbers. 



In the case of livestock only the inferior females can be dis- 

 carded, because in working with adults the expense of discarding 



