148 SOUTHERN FIELD CROPS 



rivers succeeds anywhere in the cotton-belt. Corn growers 

 just north of the cotton-belt are able to use seed from a still higher 

 latitude, but here, too, native improved varieties and locally 

 grown seed are usually more satisfactory than seed corn from a 

 widely different climate. 



LABORATORY EXERCISES 



Comparison of ears. 



(1) Select 5 or 10 plants with ears high above the ground and 

 record the average height above ground of the node bearing the 

 upper ear. 



(2) Make the same record for 5 or 10 plants in the same field 

 with ears low on the stalk. 



(3) If practicable, compare the maturity and weights of the 

 shucked ears on the two types of plants just mentioned. 



Upper and lower ears. 



(4) Select ten plants, each bearing two well-developed ears. 

 Shuck and compare the weights of 



(a) the ten upper ears and 



(6) the ten lower ears. 



(c) Does the upper or the lower ear develop and mature first? 



(5) TIP, BUTT, AND MIDDLE GRAINS. Make germination tests 

 of 100 tip grains, 100 butt grains, and 100 from the middle of 

 the ' ear. 



(6) VARIATION. Record for two plants of the same variety as 

 many points of difference as you can discover. 



What does this suggest as to the advantages of seed selecting 

 and breeding ? 



Color of grains. 



(7) Soak kernels of red and yellow corn, separate the coats, and 

 determine in what part of the grain each color is located. 



Barren plants. 



(8) Determine in any field the percentage of barren stalks. 



