Pigeonpea [Cajanus cajan (L.) Millsp.] belongs to the genus-Cajanus, subtribe-Cajaninae, tribe- Phaseoleae, order-Fabales,family-Fabaceae and sub-family Faboideae. Several edible beans like Lablab, Dolichos, Phaseolus, Vigna and Cajanus come under tribe Phaseoleae but in the sub-tribe Cajaninae, only one species, Cajanus cajan has been domesticated and cultivated. The species belonging to Cajaninae have peculiar vesicular glands on the leaves, calyx and pods which deposit asticky substance on their surface. It is the second most important pulse crop grown in India.