PLANT BIOLOGY 



numbers of plants with more 

 or less of the desired quali- 

 ties ; from the best of these, 

 he may again choose ; and so 

 on until the race becomes 

 greatly improved (Figs. 5, 6, 

 7). This process of continu- 

 ously choosing the most suita- 

 ble plants is known as selec- 

 tion. A some- 

 what similar 

 process pro- 

 ceeds in wild 

 nature, and it 

 is then known 

 as natural se- 

 lection. 



Fig. 6. — Flax Breeding. 



A is a plant grown for seed production; 

 B, for fiber production. Why ? 



Suggestions. 

 ■ — 6. Every pu- 

 pil should un- 

 dertake at least 

 one simple ex- 

 periment in se- 

 lection of seed. He may select kernels from the 

 best plant of corn in the field, and also from the 

 poorest plant, — having reference not so much to 

 mere incidental size and vigor of the plants that 

 may be due to accidental conditions in the field, 

 as to the apparently constitutional strength and 

 size, number of ears, size of ears, perfectness of 

 ears and kernels, habit of the plant as to sucker- 

 ing, and the like. The seeds may be saved and 

 sown the next year. Every crop can no doubt 

 be very greatly improved by a careful process 

 of selection extending over a series of years. 

 Crops are increased in yield or efficiency in three 

 ways : better general care ; enriching the land 

 in which they grow ; attention to breeding. 



Fig. 7. — Breed- 

 ing. 



A, effect from breed- 

 ing from smallest 

 grains (after four 

 years), average 

 head; B, result 

 from breeding from 

 the plumpest and 

 heaviest grains 

 (after four years), 

 average head. 



