166 IMPROVEMENT OF PLANTS 



Plant the same kind of seed in each box. Cover the first box with red glass, 

 the second with blue glass, the third with green glass, the fourth with yellow 

 glass, the fifth with brown glass, and the sixth with clear window glass. 

 Put the boxes where they will have free access of sunlight and air. Note 

 the results and explain. 



3. Plant seed in three boxes. Place the first one in the cellar or in a dark 

 room, put the second one in a well-lighted room, but keep the plant in the 

 shade, and put the third one outdoors where it can have plenty of sunlight 

 and air. Note results in the growth of the stems and explain. Also note 

 the color of each of the three plants and explain. 



4. Make experiments in pruning on tomato plants, peas, beans, and other 

 plants. 



5. Prepare grafts of various kinds. 



6. Illustrate budding. 



7. Test seed for vitality and purity. 



QUESTIONS 



1. Discuss the origin of domestic plants. 



2. On what three things does plant improvement depend ? 



3. Discuss the effect of change in the food supply. 



4. What effect on the plant has (a) the supply of light ? (6) the kind of 

 color of light ? 



5. Discuss (a) heliotropism, (6) diaheliotropism. 



6. Discuss variation produced by pruning. 



7. Name the objects of pruning. 



8. Describe the proper method of pruning. 



9. Discuss root pruning. 



10. Discuss the proper time for pruning. 



11. Explain variation due to cross fertilization. 



12. Discuss bud variation. 



13. Discuss the law of heredity. 



14. Explain the method of selection. 



REFERENCES 



Improvement of Animals and Plants, Davenport. 

 Plant Breeding Experiments of Burbank and Nilsen, De Vries, 

 Scientific Aspects of Luther Burbank, David Starr Jordan. 

 Propagation of Plants, Andrew S. Fuller. 



