HYBRIDIZING — MENDEL'S EXPERIMENTS 387 





factors could be improved but nothing new has been produced. In 

 selecting wheat, for example, we might breed for a number of 

 different characters, such as more starch, or more protein in the 

 grain, a larger yield per acre, ability to stand cold or drought or 

 to resist plant disease. Each of these characters would have to 

 be sought separately and could be obtained only after long and 

 careful breeding. Selection of seed is most important ; but in 

 order to produce new varieties of plants, another method is used, 

 known as hybridizing. 



Hybridizing. — We have already seen that pollen from one 

 flower may be carried to another of the same species and produce 

 seeds. If pollen from 

 one plant is placed on 

 the pistil of another of 

 an allied species or va- 

 riety, fertilization may 

 take place and new 

 plants be eventually pro- 

 duced from the seeds. 

 This process is known as 

 hybridizing, and the 

 plants produced by this 

 process known as hy- 

 brids. This process is a 

 most painstaking one, if worth-while results are to be obtained. 

 The two plants to be crossed must be selected with great care, 

 they must be carefully protected from possible self-pollination 

 and the transfer of pollen must be so restricted that no pollen 

 except the desired kind shall reach the pistil. After the transfer 

 of pollen, the flower must be covered, to prevent any other than 

 the desired pollen from reaching the pistil. 



Hybrids are extremely variable, and often are apparently unlike 

 either parent plant. Most hybrids have to be perpetuated by 

 means of some of the methods of vegetative propagation, as they 

 rarely breed true and often do not produce seeds. 



Heredity and the Work of Gregor Mendel. — By far the most 

 important discovery for the plant and animal breeder was made by 

 Gregor Mendel, the abbot of a monastery at Brunn, in what is 



In artificial pollination parts of the flower 

 (shaded) are cut away, leaving only the pistil. 

 Pollen is carried on a brush to the stigma, and 

 then the pistil is covered with a paper bag. 



