Groundnut-or peanut as it is also called-is a four-foliate legume with yellow sessile flowers and subterranean fruits. Native to South America, it originated between southern Bolivia and northern Argentina from where it spread throughout the New World as Spanish explorers discovered its versatility. Today, farmers in Asia and Africa also cultivate it. It is grown under a wide range of environmental conditions in areas between 40 degrees South and 40 degrees North of the equator.

The main use of groundnut is as a source of edible oil, but the high oil and protein contents also make it an important food crop.

In trade, the bold-seeded types are referred to as Virginia, the small seeded as Spanish, and a third type Runner is also recognized. The flowers are born in the axils of the leaves mostly near the base of plant and have generally yellow petals. It is a self pollinated crop. After fertilization stalk of ovary elongates and forms peg which contains fertilized ovules at the tip. The growth of peg is positively geotropic until it penetrates soil to some depth (7 cm). The tip then becomes diageotropic and ovary starts developing into a fruit called pod which contains seeds. Generally it takes about 60 days from fertilization to full pod maturity.

The ideal growing conditions for groundnut are well-drained, light colored, loose friable, sandy loam soil, availability of optimum moisture in pod zone, and an optimum mean daily temperature of about 30 0C. It can be grown either as a sole crop or in combination with other crops in inter or mixed cropping. Early leaf spot, late leaf spot, rust, and Sclerotium rolfsi among fungal diseases; bud necrosis virus, tomato spotted wilt virus, peanut stripe virus, and rosette among virus diseases; and jassids, thrips, termites, leaf miner, Spodoptera, and white grub among insect pests, and aflatoxin contamination are important biotic factors. Among abiotic stresses drought, low pH, and low temperatures are important. These occur in various combinations in Asia, Africa, And Americas.