Department of Forestry and Environmental Science
UNIVERSITY OF SRI JAYEWARDENPURA, SRI LANKA ../
FORESTRY AND ENVIRONMENT SYMPOSIUM
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|FORESTRY SYMPOSIUM 1996|
J M D T Everad* and M Katz**
*Coconut Research Institute, Lunuwila
** University of New England, NSW, Australia
Accurate estimation of genetic distances is vital in conservation of heterogeneous tree populations such as coconut. Conservation of coconut germplasm currently operates by selection and preservation of ecotypes and biased collections based on economic traits. Such selection is likely to misrepresent the natural variability of the palm and hence a DNA fingerprinting system, RADPs (Random Amplified Polymorphic DNAs) was proposed.
RADPs were investigated in 19 coconut types planted at the Coconut Research Institute, Sri Lanka using random primers of 10-12 nucleotides. DNA extracted from coconut leaves were pooled from four individuals to represent each heterozygotic coconut type. Thirty eight primers were tested in the RADP-PCR and polymorphic bands were scored for the presence and absence in the respective types. Pair-wise genetic distances were calculated using Nei and Li's coefficient and the cluster analysis was performed from the resultant distance matrix.
Eighteen primers detected a total 91 polymorphic bands across the coconut types screened. All these RADPs were clear and reproducible over repeated runs. Grouping of 19 coconut types based on these RADPs matched almost perfectly with the existing taxonomic grouping indicating the applicability of RADPs as a sound genetic marker for characterization of coconut genetic resources.
RADP technique is simple and rapid. It can be developed without previous information on DNA of the target plant. The cost is affordable for developing countries. RADP technique is now widely applied in breeding and conservation of heterozygous perennial crops and forest trees.
Department of Forestry and Environmental Science,