Botanists estimate there are about 350,000 plant species and about 300,000 of these grow on land. The dominant and most important are the 195,000 flowering species, most of which produce edible parts potentially useful to people. The world's food supply is obtained either directly or indirectly from the abundance of plant species, but fewer than 100 are used for food. World-wide, about 50 species are cultivated actively, and as few as 17 species provide 90% of man's food supply and occupy about 75% of the total tilled land on earth. They include wheat (Triticum aestivum), rice (Oryza sativa L.), corn (Zea mays L.), potato (Solanum tuberosum), barley (Hordeum vulgare), sweet potato (Ipomoea batatos), cassava (Manihot esculenta), soybean (Glycine max), oat (Avena sativa), sorghum (Sorghum bicolor), millet (Pennisetum typhoides), rye (Secale cereale), peanut (Arachis hypogaea), field bean (Dolichos lab-lab var. purpurius), pea (Pisum sativum), banana (Musa paradistaca), and coconut (Cocos nucifera). Eight cereal grains - wheat, barley, oat, rye, rice, maize, sorghum and millet provide 56% of the food energy and 50% of the protein consumed on earth.

Plant genetic resources for food and agriculture (PGRFA) encompass the diversity of genetic material in both traditional varieties and modern cultivars, as well as crop wild relatives and other wild plant species used as food. Plants provide the food, the feed of animal species and support the livelihoods of every person on earth. These are the farmers most essential inputs and provide the raw material for plant varietal improvements and a reservoir of genetic adaptability to buffer against harmful environmental and economic change. Reliable and sustainable improvements in crop yields are needed to meet the demands of population growth and to overcome the food insecurity and undernourishment that some 800 million people face today. This requires not only improved management and productivity of plants and animals, but enhanced productivity and efficient use of soil and water resources and ecosystems. Soil organisms and healthy soils are an important component of well functioning and productive agricultural ecosystems.

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