PLANT Cotors In MAIZE 119 
r’, 77, r*, are assumed and genetic formulae are assigned to the several 
color types as follows: purple, A B Pl; sun red, A B pl; dilute purple, 
A 6b Pl; dilute sun red, A b pl; brown, a B Pl; green, a B pl, ab Pl, ab pl; 
all these having in addition R’, r’, or r™ The factor R™ is assumed 
to be the causal factor for green anthers and silks in purple, sun red, 
dilute purple, and dilute sun red types, and R’ and r’ are assumed to have 
the same effect on purple and sun red and to insure colorlessness (green 
type) thruout in what would otherwise be dilute purple and dilute sun red, 
the R series having no effect on brown, except for r, which intensifies 
brown as well as purple and dilute purple. . Of the R series, R’ is dominant 
_and 7’ is recessive for both plant and aleurone color, r’ and r” are dominant 
for plant and recessive for aleurone color, R’ is recessive for plant and 
dominant for aleurone color, and R” is dominant for aleurone color and 
also for plant color except of the anthers and the silks, for which it is 
recessive. The A a pair is concerned with both aleurone and plant color, 
and the aleurone pairs Cc and Pr pr are assumed to exert a modifying 
effect on certain plant colors. 
| The principal hypotheses involved are shown to be in keeping with 
observed facts when subjected to practically all the available genetic 
tests, such as backcrosses of F; with multiple recessives, behavior of F» 
types in later generations, intercrosses of the several F. types, relation 
of aleurone color to plant color, linkage of certain plant-color types with 
‘normal- and liguleless-leaf types and of other plant-color types with 
yellow and white endosperm. Approximately 32 per cent of crossing- 
over is reported between B b and Lg lg and about 20 to 30 per cent between 
Pl pl and Y y. 
