In situ and Ex situ Conservation of Commercial Tropical Trees - ITTO

337Sampling strategyThe objective of sampling genetic materials for ex situ conservation is to captureas much genetic variation as possible within practical limits. Through this analysisof putative families (wildlings collected from a small area) and the referencepopulation (regarded as a representative of the natural population in Jambi),genetic characteristics of natural populations were estimated and used as aguide in developing sampling strategy.When collecting wildlings for conservation purposes, four differentschemes of collection could be considered. First, very large number of wildlingsfrom one or a few narrow areas. Second, a few wildlings/plot but from a widearea covering the whole population. Third, an intermediate number of wildlingsfrom an intermediate number of plots, wherein the number of plots is more thanthe number of individuals per plot. Fourth, an intermediate number of wildlingsfrom an intermediate number of plots wherein the number of individuals perplot is more than the number of plots.For the first scheme, the chance of losing a certain amount of genes ishigh because the total number of alleles per locus was smaller in the putativefamilies than in the reference population. Therefore, this scheme should beavoided. The second scheme could be the best if the same genetic compositionas the natural population is to be conserved. This scheme, however, is timeconsuming and laborious. The third and fourth schemes are biologically similarbut differ greatly in terms of time and labour. Both of them would capture highgenetic diversity and the loss of genes would be minimum. Moreover, whenthese schemes are carried out, increasing heterozygosity due to the Wahlund’sprinciple could be expected. Wahlund’s effect occurs when two isolatedpopulations that are differentiated are combined. The genetic characteristicsof the wildling population of S. leprosula from a limited area were specific inthis study, and this is the same effect as in isolated populations. Scheme fourwould be more efficient than scheme three and less laborious. If the otherpopulation possess similar genetic characteristics, a sampling strategy basedon scheme four could be sufficient.AcknowledgementsThe study was carried in support of ITTO Project PD 16/96 Rev.4(F) (Ex situConservation of Shorea leprosula and Lophopetalum multinervium and TheirUse for Future Breeding and Biotechnology). Funding for this study was providedby government research budget of Indonesia. Support from JICA Forest TreeImprovement Project Phase II in Indonesia is also acknowledged.