Loss of the genetic diversity of some of the world's crops has accelerated in recent decades, with many crops becoming increasingly susceptible to diseases, pests, and environmental stresses. A global network of gene banks has therefore been established to provide plant breeders with the genetic resources necessary for developing more resistant crops that will enable farmers to maintain high yields. Most of these gene banks now store the germplasm of only the major crops such as cereals, potatoes, and grain legumes. Cultivated varieties of these crops are conserved as well as wild species that might otherwise become extinct. Tropical cash crops such as bananas and coconuts are also important food crops in many Third World countries, and more effort needs to be made to conserve the germplasm of these crops as well as of other important plants such as plantation crops, medicinal herbs, and fruit and timber trees.

Taxonomic investigations of the variation within Beta vulgaris sensu lato, including the use of numerical techniques, have led to the following conclusions: 1. The variation in morphology of the modern cultivated types of beet exhibit noda in a continuous variation pattern. 2. Microspeciation within wild forms of B. vulgaris is considered to have occurred in the centre of diversity, while in some areas hybridization within Section Vulgares has produced a complex taxonomic situation. 3. Because of the existence of this continuous variation, the classification within the section has been simplified. A new theory for the origin of cultivated beets is proposed.

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