Nature of inheritance of genes controlling purple pericarp colour in the cross AC. 806 × Pirurutung and black hull colour at maturity in the combination IR 8 × JBS. 674A was studied. Both AC. 806 and Pirurutung have purple pericarp. The expression of purple pericarp was controlled by two pairs of duplicate genes Prp1 and Prp2.
Straw hull colour in IR 8 was found to be due to two pairs of dominant genes; gold hull of JBS 674A was due to the presence of the corresponding two recessive genes. The gene for the production of phenol oxidising enzyme Po is present in IR 8. Two genes Ph1 and Ph2 present in JBS. 674A are responsible for the production of the phenolic compound. Black hull colour is due to interaction of genes Ph1, Ph2 and Po.
