The commercial value of crop wild relatives is impressive. The desirable traits of wild sunflowers (Helianthus spp.) are worth an estimated US$267 million to US$384 million annually to the sunflower industry in the United States; one wild tomato variety has contributed to a 2.4 percent increase in solids contents worth US$250 million; and three wild peanuts have provided resistance to the root knot nematode, which cost peanut growers around the world US$100 million each year.
In addition to their use in breeding, crop wild relatives are also used in their wild state. A number of wild cowpea species (Vigna spp.) in Africa contribute directly to food security through consumption of their tubers, fruit and seeds. Wild yams (Dioscorea spp.) are an important source of carbohydrates and incomes in Madagascar, and wild fruits such as apple, pistachio and sea buckthorn are harvested for food in Central Asia and the Caucuses. CWR species also provide other invaluable products such as animal fodder, building materials and medicines.
The first crossings between crop wild relatives and cultivars to obtain disease resistant varieties date back to the 1890’s, with pest and disease resistance currently remaining the highest priority for breeders and CWR being used primarily for this purpose.
The increasing genetic uniformity of crop varieties combined with climate change effects makes crops more vulnerable to stress. The potato famine of the 1840s was caused by large-scale crop failures as a result of genetic vulnerability to the late potato blight epidemic - a large proportion of the susceptible potato varieties grown at that time were eliminated as the blight spread across Ireland, Europe and North America.
Devastating losses in the 1970s caused by the southern corn blight outbreak in the US maize crop further highlighted the risk of relying on a few high-yielding varieties. Genetic vulnerability has also caused large-scale rice losses in the Philippines and Indonesia. crop wild relatives are important for maintaining genetic diversity and preventing such losses, which can have serious consequences for food security.