292 



General Botany 





Fig. 182. 



Diagram to illustrate the behavior of the chromosomes during 

 vegetative cell division. {After Strasburger.) 



certain combination and to plan a definite set of crosses that will 

 bring the desired result in a few generations. 



Importance of Mendel's laws. With the above example in 

 mind, it is not difficult to see that the use of Mendel's methods 

 has greatly simplified the problems of the plant breeder and made 

 possible the early attainment of desirable combinations of charac- 

 ters by hybridizing difTerent varieties and closely related species 

 of plants. It has made it possible to breed for definite combina- 

 tions and to determine when the combinations have been secured. 



Before the discovery of Mendel's laws of inheritance, all breed- 

 ing was merely a matter of chance, and much of it is still being 

 carried on in that way because we are still ignorant of the factors 

 involved in many characters of numerous plants and animals. 

 On the other hand, many important food and ornamental plants 



I 



