Crop diversity or crop biodiversity is the variety and variability of crops, plants used in agriculture, including their genetic and phenotypic characteristics. It is a subset of a specific element of agricultural biodiversity. Over the past 50 years, there has been a major decline in two components of crop diversity; genetic diversity within each crop and the number of species commonly grown.
Crop diversity loss threatens global food security, as the world's human population depends on a diminishing number of varieties of a diminishing number of crop species. Crops are increasingly grown in monoculture, meaning that if, as in the historic Great Famine of Ireland, a single disease overcomes a variety's resistance, it may destroy an entire harvest, or as in the case of the 'Gros Michel' banana, may cause the commercial extinction of an entire variety. With the help of seed banks, international organizations are working to preserve crop diversity.