CORN 



195 



and will pay for the labor involved many times over in a better stand and 

 resulting larger yields of corn. 



Improvement by Selection and Breeding. — The ear row method is 

 the most satisfactory way of improving corn along any line. This method 

 is based on the principle that like begets like, but fortunately this prin- 

 ciple is not rigid. It is the variation in the progeny of any parent plant that 

 enables us, through selection, to improve the variety, and it is the tendency 

 for like to produce a larger percentage of progeny, differing but slightly 

 from the parent that enables us to make progress in plant improvement. 



Corn improvement by selection is easy, because the plant is large 

 and its characteristics plainly visible; because the variations are suffi- 

 ciently marked and frequent to enable man to select individuals with 



A Good Germination Box* Seven Days After Planting. 1 



The box is filled with wet sand and marked into checks by means of cord stretched 

 across the top at even intervals. 



desirable characteristics, and also because of the large number of plants 

 that can be secured from the individual and the consequent rapidity of 

 multiplication. » 



Corn breeding is somewhat difficult because of the natural cross- 

 fertilization and the impracticability of keeping the breed pure, and also 

 because close and self-fertilization are difficulties that must be guarded 

 against. None but the choicest ears selected for desirable qualities of 

 both ear and plant should be used in the breeding plat, and any ears that 

 do not show a high standard in the germination test should be rejected. 



The selected ears should next be tested for yield and prepotency. 

 The ears should be numbered and a portion of each planted in a separate 

 row of a test-plat having uniform fertility. The rows should be sufficiently 

 long to contain about 200 plants. This will require about one-fourth of 

 the kernels of each ear. The rows should bear the same numbers as ears 



> From Farmers' Bulletin 400, U S. Dept. of Agriculture. 



