118 R. A. EMERSON 
the reverse of this. For example, 7” and r™ are recessive for aleurone 
and dominant for plant color, and R’ is dominant for aleurone and 
recessive for plant color, while R’ is dominant and 7% recessive for both | 
aleurone and plant colors. 
SUMMARY 
In this account, six major plant-color types of maize, purple, sun red, 
dilute purple, dilute sun red, brown, and green (colorless), together with | 
the subtypes, weak purple, weak sun red, green-anthered purple, green- | 
anthered sun red, and five genotypes of green, are described and illustrated, 
and their environmental and genetic relations are discussed. 
The sun red and dilute sun red types are shown to be dependent on | 
light for the development of their color, while the purple, dilute purple, 
and brown types develop their characteristic’ colors in darkness. 
Diversities of temperature and of soil moisture are shown to have no 
direct effect on the formation of maize plant colors but to have an indirect 
relation to them thru their influence on soil fertility, which in turn bears 
a definite relation to the development of the purple-red series of plant 
color, anthocyanins, but little or no relation to brown. Sun colors 
particularly are shown to be markedly intensified by infertile soil. It is | 
noted that the several types of the purple-red series are sharply 
differentiated when grown on fertile soil, but that their characteristic 
differences are largely masked by growth on infertile soil, while the | 
brown-green series is most readily distinguished from the purple-red 
series, especially in the seedling stage, if grown on infertile soil. It is 
suggested that the effect of infertile soil may be due to a deficiency of 
nitrogen, and perhaps of phosphorus. Observations indicating a close 
connection between the accumulation of carbohydrates and strong colora- | 
tion are reported, and the inference that the effect of infertile soil is 
brought about thru checking growth without inhibiting photosynthesis, | 
thus allowing an accumulation of carbohydrates, is discussed. 
In an attempt at a genetic analysis of the several plant-color types, 
data accumulated during a period of some ten years, and involving an | 
examination of approximately 680 progenies and not less than 48,000 | 
individual plants, are reported. As an interpretation of the results! 
obtained from the more complex crosses, the allelomorphic pairs A a 
and Pl pl, and the multiple allelomorphs B, B”, b*, b, and R’, R’, R™, 
