Zereshk is the Kurdish and Persian name for the dried fruit of Berberis vulgaris, which are widely cultivated in Iran. Iran is the largest producer of Zereshk in the world. Zereshk and saffron are produced on the same land and the harvest is at the same time. About 500 kinds of seeded barberries grow in various parts of the world, but Iran is the only seedless barberry producer in the world. seedless barberry is resistant to cold weather and grows well in mountain areas with cold winters.

The South Khorasan province in Iran is the main area of Zereshk and saffron production in the world. Around 14,000 hectares of land is used for growing barberry in South Khorassan Province. Most of the seedless barberry is produced in South Khorassan Province.

The main agricultural products of South Khorasan province are Zereshk, saffron, pistachio, and almond.

Zereshk is widely used in cooking, imparting a tart flavor to chicken dishes. It is usually cooked with rice, called Zereshk polo, and provides a nice meal with chicken.