Plant genetic resources and their conservation
Of the more than 10 million species of living organisms, only about 10 percent have survived the ice ages (first narrowing), the spread of agriculture (second narrowing), and scientific plant breeding (third narrowing). Of the approximately 300 000 species of flowering plants, only 200 have been domesticated and today only eight crops supply the world's human population with about 75 percent of its food. However, in the second phase, the narrowing of plant diversity above species level was compensated for by an increase of diversity within crops. The spread of agriculture was largely due to this process of crop evolution under domestication. Genetic erosion started during the third phase. The need to conserve genetic diversity was recognized some 50 years ago. Today, over 1 million accessions of the most important crops are stored in nearly 100 seedbanks. However, more genebanks to store field collections and in vitro cultures are needed for species with recalcitrant seeds or those vegetatively propagated, for which in situ conservation is not practical. Despite all these efforts, it has been estimated that for some genera, especially for wild species, the representation of collected material is far from adequate. Urgent action is indicated for wild relatives in many ecosystems. Genetic resources are crucial to the development of biotechnology, and genebanks are a prime source of material in this field
| Main Authors: | , , , , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Published: |
Ibadan (Nigeria) IITA
1992
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