22 THE ESSENTIALS OF AGRICULTURE 



QUESTIONS AND PROBLEMS 



1. Prepare a list of your best local examples of plants and animals 

 which are the results of improvement over less desirable ancestors. 



2. What are the local cultivated plants which .have been longest culti- 

 vated by man ? 



3. How was the Concord grape developed? the Burbank potato? 



4. What were the methods by which Patrick Shirreff developed new 

 strains of wheat? 



5. What is meant by variation among plants and animals? In man's 

 problems of improvement of plants and animals, what use does he make 

 of variations? 



6. In what respects is the " ear-row " method of selecting plants better 

 than "mass" selection? 



7. Explain what is meant by crossing plants or animals. In what ways 

 may crossing contribute to the making of new varieties ? 



8. Explain briefly how Mendel discovered the law known as Mendel's 

 Law. 



9. How does a knowledge of Mendel's Law help the breeder? 



10. Explain and illustrate the meaning of " The more highly developed 

 plants and animals become, the more dependent are they upon man." 



11. What plants and animals are most likely to be chosen as subjects 

 for development? 



REFERENCES 



BAILEY, L. H. The Evolution of our Native Fruits. The Macmillan 



Company. 



BAILEY and GILBERT. Plant Breeding. The Macmillan Company. 

 COULTER, J. M. Fundamentals of Plant Breeding. D. Appleton and 



Company. 

 DARBISHIRE, A. D. Breeding and the Mendelian Discovery. Cassell and 



Company. 

 DARWIN, CHARLES. Variation of Animals and Plants under Domestication. 



2 vols. D. Appleton and Company. 



DE CANDOLLE, A. Origin of Cultivated Plants. D. Appleton and Company. 

 SHALER, NATHANIEL. Domesticated Animals. Their relation to man and 



to his advancement in civilization. Charles Scribner's Sons. 



