PLANT GENETIC RESOURCES IN BOTANICAL GARDENS

Abstract

The world’s botanical gardens house some 80,000–100,000 species, and ca. 15,000 species hereof are threatened in the wild. However, representation of natural biodiversity is imbalanced. There is strong bias towards certain plant families and genera, and towards certain functional groups. Apart from this, bias towards species from temperate regions as a result of the imbalance in geographic distribution of botanical gardens is obvious. Tropical regions and the southern hemisphere are highly underrepresented. Most species cultivated in botanical gardens are on an average represented by only two or three specimens, and the genetic diversity within wild species is not reflected. Further limitations include poor documentation and poor maintenance. These limitations reduce the value of the collections as plant genetic resources. However, botanical gardens are the standard institutions for ex situ conservation and propagation of wild plants and should be the main authorities for wild plants. With their huge collections on display botanical gardens are the most effective multipliers for increasing public awareness of the value of biodiversity and conservation needs. There is growing awareness of the ecological, economic and cultural significance of wild plant species and their potential value as genetic resources. Botanical gardens should establish seed gene banks for wild plants for promoting integrated conservation efforts and for protection and conservation of our natural plant genetic resources. They should establish database networks and should provide information services for science, politics and the general public. Botanical gardens play a significant role in promoting public awareness of the value of biodiversity. They have a remarkable potential to contribute to the conservation of plant genetic resources. PLANT GENETIC RESOURCES The Convention on Biological Diversity (CBD) defines genetic resources as “genetic material of actual or potential value” (CBD 1992, article 2), in which “genetic material” means any material of plant, animal, microbial or other origin containing functional units of heredity. Plant genetic resources (PGR) “represent plants or parts of plants which are capable of generative or vegetative propagation with actual or potential value” (FAO Commission on PGR). Plant genetic resources may be classified into eight groups according to the respective conditions for use and conservation (Keller et al., 2002): agricultural crops (food, fodder, raw material); pasture plants (meadows and pastures for fodder production); vegetables; fruit crops (fruit trees and shrubs); special crops (medicinal plants, spices, aromatic and dye-plants); ornamentals (flowers, shrubs, ornamental woody plants); forest plants; wild plants. About 30,000 plant species are considered edible. Of these, 7,000 have been cultivated or collected by humans (FAO, 1998). About 120 food crops are of importance on a national scale. Only 30 crop species make up 90 % of the worlds calorie intake. In some countries, especially Africa and South America, wild species contribute a significant source of food in addition to cultivated species. The markets for plant genetic resources products is immense and according to Ten Kate and Laird (1999) annually somewhere between 500 and 800 billion US $.