Characterization and inheritance of dwarfing genes of pigeonpea

Abstract

Pigeonpea [Cajanus cajan (L.) Millsp.] cultivars have excessive vegetative growth and are not amenable to efficient crop management practices such as foliar insecticide application and mechanized field production. This study was conducted at the ICRISAT Center in India to characterize three easily distinguishable dwarf pigeonpea phenotypes (D6, PD1, and PBNA) with respect to some morphological traits and to study the inheritance patterns for dwarfing genes. Six crosses involving the dwarf lines and tall cultivars were studied. In 1986, the parents, F1, and F2 generations were grown and in the following year, testcrosses and F3 progenies were evaluated along with their respective parents. Each population was phenotypically classified relative to parental type as tall or dwarf. The chi-square analyses showed that the dwarf phenotype in each of the three lines was controlled by a single recessive gene in homozygous state. The D6 and PD1 lines had similar alleles (t3t3) whereas PBNA had a different allele (th3th3) for dwarfness, which was recessive to the D6/PD1 allele, thus constituting a multiple allelic series.