Tissue culture is the growth of plant tissues or cells in a sterile medium separate from the organism. It has several applications, including the large-scale commercial production of identical plants, conserving rare species, screening plant cells for desirable traits, and producing valuable compounds from plant cells in liquid culture. Tissue culture also allows for crossing distantly related plant species and producing clean plant material free of viruses. Its advantages include producing many copies of plants with beneficial properties, allowing plant production anytime regardless of climate, and eliminating plant infections. However, its disadvantages are the high costs of equipment for large-scale production and the need for careful, trial-and-error work that depends on the plant species.