190 FIELD CROPS FOR THE COTTON-BELT 



ter than one borne in an upright position (Figs. 36, 

 37). 



The type assumed by high-yielding strains of corn varies 

 in different regions. Therefore the ideal type for one set 

 of conditions will vary from that growing under conditions 

 markedly different. The acclimated high-yielding strains 

 have adjusted themselves to their surroundings, and corn 

 breeders should select their seed from typical plants that 

 are in harmony with natural conditions. 



230. Defects in southern varieties. The most serious 

 defect possessed by the bulk of the corn planted in the 

 south is the lack of those hereditary qualities such as vigor 

 and prolificacy that make for higher yield. In addition to 

 these there are a number of qualities which may or may 

 not affect yield, but which, because of their relation to the 

 ease of harvesting, the ability of the plants to resist storm, 

 or the quality of the grain produced, should receive careful 

 attention by corn growers. The most important of these 

 qualities are: (1) lower position of ear on the plant; 

 (2) strength, or power of the plant to stand up; (3) tend- 

 ency for the mature ears to turn downward; (4) more com- 

 plete covering of the tip by shucks; (5) a decrease in the 

 size of the plant in some varieties. All of the above qual- 

 ities, including vigor and prolificacy, have been shown to 

 be hereditary and are therefore under the control of the 

 corn breeder. 



231. Barren plants. The tendency in corn to pro- 

 duce stalks without ears is generally held to be hereditary, 

 although it is to a large degree dependent on climatic condi- 

 tions. That this tendency in corn is to an extent hereditary 

 is shown by the fact that seed corn that has been fertilized 

 by the pollen from barren stalks often gives rise to an in- 

 creased number of useless plants. De Vries makes reference 



