The lychee (Litchi chinensis Sonn) an important sub-tropical evergreen fruit crop belonging to family Sapindaceae, is believed to have originated in China, where it has been grown in Southern Guangdong state for thousand of years. It is highly specific to climatic requirements and probably due to this reason its cultivation is restricted to few countries in the world. In India, lychee was introduced in the 18th century through Burma, and from there, it spread to many countries. India and China account for 91 percent of the world lychee production but it is mainly marketed locally. In India, 428,900 metric tonnes of lychee is produced annually from 56,200 hectares. Lychee being exacting in climatic requirement is confined to a few states with 74 percent of production recorded in Bihar. In this state, lychee is the livelihood for millions of people as it provides both on-farm and off-farm employment. Small and marginal farmers get additional income from lychee plants in their homesteads. Thus, lychee cultivation is the livelihood security for a large population, especially in the state of Bihar.
The lychee tree is handsome, dense, round-topped and slow growing with evergreen leaves having 6-9 elliptic oblong and lanceolate abruptly pointed leaves. Colour of leaves varies from light green to dark green. Greenish white or yellowish flowers are borne in clusters. Fruits are round or heart shaped having thin, leathery skin. The colour of fruits varies with cultivar, and is red or rose or pinkish. The edible portion or fruit is the aril, which is immediately beneath the skin. Flavour of the aril varies with cultivar, which is distinctive. Seeds are bold but in some cultivars seeds are partially developed, due to failure of pollination, referred to as ‘chicken-tongue’ seed. The trees with small seeded fruits are prized because of the greater portion of pulp.