1. P^rg, an allele at the P locus.

In a strain of colorless pericarp a plant with kernels of colorless pericarp with a red 2 mm large girdle around the kernels in the pericarp was observed. Through self‑pollination a homozygous genotype for this character was raised. Some plants of the mentioned character were crossed with homozygous genotypes: (a) colorless pericarp and (b) orange pericarp. In the F₁ generation the kernels of the cross to (a) have had a colorless pericarp with a red girdle and the kernels of the cross to (b) an orange pericarp with a red girdle.

The F₁ generation of the cross to (a) has been outcrossed with plants of colorless pericarp and of the cross to (b) with plants of orange pericarp. The symbol P^rg for the factor for kernels with red girdle was used.

Cross (a):
P1 :	P^rg/P^rg x P^W/P^W
F1 :	P^rg/P^W
F1 outcrossed :	P^rg/P^W x P^W/P^W
Progeny :	P^rg/P^W -	486 colorless pericarp with a red girdle,
	P^W/P^W -	471 colorless pericarp
	Total -	957 plants

Cross (b):
P1 :	P^rgo/P^rgo x P^o/P^o
F1 :	P^rgo/P^o
F1 outcrossed :	P^rgo/P^o x P^o/P^o
Progeny :	P^rgo/P^o ‑	623 orange pericarp with a red girdle,
	P^o/P^o -	639 orange pericarp
	Total ‑	1262 plants

It follows that the character red girdle P^rg is allelomorphic to P^W and P^o, respectively.