Field Gene Banks, Botanic Gardens, In Vitro, DNA and Pollen Conservation

Abstract

The conservation of vegetatively-propagated crops such as potato, cassava, yams, sweet potato, sugar-cane, coffee, cocoa, rubber, coconut, banana, mango and many temperate fruit trees amongst others presents special problems for Ex Situ conservation. It will be seen that two categories are dealt with here. The first of these is relatively long-lived trees or bushes, whilst the second involves root or tuber-bearing species. Although some of the crops conserved in this way are sexually fertile, it is often not convenient to propagate them commercially from seed because of high levels of genetic heterozygosity, and breeders and horticulturalists commonly require uniform clones. Field gene bank conservation involves the collecting of materials from farmers’ fields and gardens, or even from wild locations, and transferring them to a second site where they can be planted and monitored. It is also difficult to keep vegetatively-propagated plants free from viruses, and this infection leads to degeneration of clonal stocks. On the other hand, reproduction from true seed, if this is possible, generally eliminates virus diseases.