2. Husk color.

(a) Rose‑wood (self or variegated) husks is a character due to a new effect of the P series as reported already in 1948. This color type is very common in South American maize, from the Rio Grande to Central Brazil (Bororo Indians). A North American hybrid obtained through Dr. M. M. Rhoades with white pericarp and red cob, proved, under our conditions to have light rose‑wood colored husks. The character appears only when the ear is picked after the plant has dried completely in the field.

As in other pericarp colors, the deeper colors are dominant over the lighter ones, and color is dominant over colorless. The types so far studied and their proposed symbols are as follows:

Pericarp	Cob	Husks
p^rrr red	red	rose‑wood
P^VVV variegated	variegated	variegated rose‑wood
p^wrr colorless	red	light rose‑wood
p^wrf colorless	red	rose‑wood or margins.

Crosses of p^rrr with a testers showed that dominant A is necessary for the formation of the rose‑wood color in the husks. The aP type has brown pericarp with colorless husks. Crosses with P tester and sr prove that we are dealing with a P gene in chromosome 1.

(b) Purple husk color is due to two genes. Crosses with Abpl gave in F₂ the following: Total = 1214, purple husks = 669, white husks 545. c² for 9:7 = 0.64.

Crosses with ABPl showed in the five strains with colored husks studied that four were of the constitution AbPl, in spite of the fact that plants in the field appeared typically sun red with gray anthers. The fifth strain with lighter colored husks had the constitution Abpl.

Crosses with a North American tester AbPl gave 3 colored husks to 1 colorless in F₂. A sr tester proved that the P gene is not responsible for the purple husk. Crosses with a tester gave in F₂ a segregation and green plants with brown husks appeared. These plants are homozygous aa. The color is just the same as in the Colombian races which previously we called "Havana".

This has led to the conclusion that dominant A is necessary for producing purple husks. Thus we believe that purple husk is due to a new dominant gene, reinforced by the Pl factor and requiring the presence of the A factor, and propose the symbol Ph ph for this new gene.