MAIZE BREEDING 187 



necessary for the production of red aleurone. These Emerson 

 (1918) has called R, C, and A. In addition to these three 

 factors, Pr, in either the simplex or duplex condition, gives 

 purple aleurone. An inhibitory factor which was called / was 

 first discovered by East and Hayes (1911). When this is present, 

 the aleurone layer is colorless. Races of white corn exist which 

 contain some but not all of the factors necessary for the produc- 

 tion of aleurone color. Certain crosses between white races 

 give colored aleurone. With five or six factors involved, it 

 becomes apparent that segregation in certain cases may be in a 

 simple 3:1 ratio, while segregation in other crosses may give 

 extremely complex ratios. There are various intensities of the 

 purple color in different races. These have been discussed in 

 detail by Emerson (1918). Over waxy or floury endosperm 

 purple aleurone gives a dull black appearance. With a varia- 

 tion in color of the endosperm from white to dark yellow there 

 is a corresponding variation in color of the aleurone from purple 

 to brownish shades. These differences in aleurone appearance 

 are due to the inheritance of other genetic factors for endosperm 

 characters beside those which govern the ability to produce 

 aleurone color. There are some genetic differences in aleurone 

 colors which are not related to the underlying endosperm 

 characters. Two color patterns have been mentioned by 

 Emerson under the names speckled and dark-capped. The 

 color is found on the crown of the seed and varies from a mere 

 speck to a large spot. Both color patterns are recessive to 

 normal or self-color. Aside from these color patterns which are 

 apparent in homozygous races, there are mottled colors which 

 are only obtained in the heterozygous condition. Emerson has 

 given quite conclusive proof that mottling is associated with the 

 Rr factor pair. Apparently endosperms of the constitution 

 RRR or RRr are self-colored while Rrr shows mottling. 



PLANT CHARACTERS 



Colors in Plant Organs. There is a group of anthocyan color 

 characters which are expressed in one or all of the following 

 organs: cob, pericarp, silk, tassel, i.e., glume, and in the leaves 

 and stems. There are several different character expressions 

 of a stable nature for this group of color characters. In some 

 cases the color in two or more organs may be inherited as if due 



