Genetics and Histology of a Corky-Stem Mutant in Pigeonpea

A mutant pigeonpea (Cajanus cajan (L) Millsp.) characterized by cork formation on its stems and branches was identified and designated as “corky-stem.” The inheritance of this trait was studied in the F1, F2, and BC1F1 (mutant × F1) generations of two crosses. The results suggest that the corky-stem character is governed by one recessive allele and one dominant allele, designated sm and Ck, respectively. The dominant form of the sm allele completely masked the expression of the Ck allele, resulting in a smooth stem surface. Cork formation was attributed to the development of a periderm layer which is normally absent in the pigeonpea stem.