Pistachio nut is the fruit of a treelike plant (scientific name of Pistachio Vera) that grows in clusters. The kernel is yellowish green and covered by a peel firmly adhered thereto. The enlarged nut pushes on the surrounding hard beige shell to cause a natural split, while the hull, which serves as a protective cover for the shell, usually remains intact.
The pistachio trees blooms during April and the kernel develops during the month of July. Pistachio usually ripens in 2nd half of September.
Pistachio is an old crop and most of the cultivated varieties are selections from the seedling populations.
the major producers are the Iran, USA and Turkey followed by Syria Afghanistan and others.
In Iran according to shape Pistachio categorized to Long and Round varieties, Open Mouth and Closed Mouth type. Long pistachio varieties are Ahmadaghaii called AA, Akbari called Ak, and Badami. Round Pistachio varieties are Fandoghi and Kalleghoochi (Jumbo).