204 FIELD CROPS FOR THE COTTON-BELT 



250. Degrees of relationship among com plants. — It 



is possible to have several degrees of relationship among 

 corn plants. These may be simimarized as follows: 



"1. Inbreeding, occurring when the pollen from a plant 

 fertilizes the ovules of the same plant. 



2. Close breeding, occmring when the poUen of a plant 

 fertihzes the ovules of a sister plant, or those of a plant 

 that has grown from the kernels of the same ear. 



3. Narrow breeding, occurring when pollen from a plant 

 fertihzes the ovules of a plaijit not closely related but of the 

 same variety. 



4. , Broad breeding, occurring when the pollen from a 

 plant fertilizes the ovules of a plant of a different variety, 

 or occurring when the pollen from a plant fertihzes the 

 ovules'of a plant of a different group, as between dent and 

 flint corn. 



251. The transmission of characters — Mendel's 

 law. — Inheritance in plants may be studied by two 

 methods: (1) by the statistical method of . considering 

 plants and their offspring collectively; (2) by the analytical 

 method of studying the separate characters and their 

 modes of transmission. The present conception of plants is 

 that they are composed of separately heritable imits known 

 as "luiit-characters." Examples of such unit-characters 

 in corn are: the color of the grain, cob, stem or husks; the 

 character of the endosperm; the height of the plant; sus- 

 ceptibility or immunity to disease, and the like. The law 

 governing the transmission of such unit-characters from 

 parent to offspring was first discovered by Gregor Mendel, 

 an Austrian monk, in 1865, and rediscovered by de Vries 

 and others in 1900, and is now known as, "Mendel's law 

 of hybrids." The manner in which the sphtting up and 

 redistribution of parental characters occurs in hybrids 



