24 PLANT BREEDING 



offspring with their own individuality. Others have this power in 

 a marked degree. When two parents are used which differ in cer- 

 tain respects, one or the other must dominate in fixing their differ- 

 ences upon the offspring. The characters which prevail are called 

 dominant characters; those which are overshadowed are called 

 recessant characters. 



Breeders will naturally find it advisable to breed from those 

 individuals exhibiting strong prepotent qualities. 



Careful Selection.— The plant breeder will find it necessary to 

 destroy hundreds and thousands of individuals in the selection of a 

 few which meet his ideals. Great skill is required to do this. He 

 must observe the many ways in which the individuals vary. _ He 

 must weigh in his mind the practical points and the fanciful points. 

 It is necessary for him to choose among these and retain those most 

 desired. An effort to hasten the improvement of plants is exer- 

 cising the powers given man by the Creator. This i3 an argument 



Fig. 13. — Two piles at left are the first and second grades of crop from good seed pota- 

 toes. Those at the right are from poor seed. 



in favor of artificial selection. (Fig. 13) In nature, selection seems 

 to be careless. The power of man's mind adds greatly to the 

 improvement of plants and the establishment of varieties which 

 yield infinitely better products than those found in nature. The 

 importance of seed selection is shown in figure 14. 



The breeder must know the history of the type which he is 

 trying to develop. He should keep the practical or economic as- 

 pect strongly before him. The laws of variation and heredity must 

 be strongly in his mind. 



Hybrids. — New forms are often created by crossing rather 

 distinct forms. Pollen taken from one variety of apples and crossed 

 on other varieties would produce seeds which are called hybrids. 

 A Japanese plum of one variety may be crossed with a variety of 

 European plum or American plum. The resulting offspring would 

 be called a hybrid. 



This method of producing new varieties of plants is quite com- 

 monly practiced by plant breeders. 



