Lindstrom: Heritable Characters of Maize 



133 



SEEDLINGS FROM FOUR SELF-POLLINATED EARS SEGREGATING FOR 

 FINT DEFECTIVE KERNELS, SHOWING LINKAGE 



Figure 20. When the defective grains of flint corn (Figure 16), are grown separately 

 from the normal grains from the same ear, a striking difference appears in the seedlings. 

 Above are shown alternate rows of seedlings from normal grains, and from flint-defective 

 ones. All those from defective seeds have produced albino plants. Relatively very few of the 

 defective seeds have sprouted, and even at this earh' stage the albino seedlings are evidently 

 at a disadvantage as compared with the normal ones. As the plants grow older the difference 

 will become greater. The albinos eventually will starve to death, as the absence of chloro- 

 phyll makes it impossible for them to manufacture food from sunlight and the elements 

 drawn from air and soil. 



be several different genetic types of 

 defective and abortive endosperm. It 

 so happens that this material does not 

 exhibit such clean-cut types as those 

 reported in this article. Another year's 

 work, in which the secondary modi- 

 fiers influencing the kernel type are 

 rendered pure, is necessary. 



Recent work is proving that the 

 endosperm of maize is but another 

 example of a qualitative, heritable 

 character that is dependent on a large 

 number of genetic factors for its de- 

 velopment. Besides the factors that 

 control the physical texture of the 



endosperm such as the sweet, flint, 

 dent, pop, floury and waxy factors, we 

 must now add at least a half-dozen 

 others that control directly the forma- 

 tion and complete development of the 

 endosperm itself. The recessive allelo- 

 morphs of these might be classed as 

 lethal or semi-lethal factors for endo- 

 sperm development. 



The general situatioii is similar to 

 that of another characteristic of the 

 corn plant. Chlorophyll, for example, 

 is a distinct genetic character that is 

 now known to involve at least twenty 

 separate genetic factors, ranging from 



