Is there ecological adaptation in coconut nursery seedlings stage?:a preliminary investigation

Seedlings were raised in three nurseries representing different agro-ecological regions, to test whether growing seddlings exhibited adaptation to a particular environment. Seed nuts were also selected from agro-ecologically different regions. The T x T seed nuts from the isolated coconut seed garden showed a faster rate of germination at all sites compared to Moorock seed nuts (from the North western region) or Dehigahalande seed nuts (from the Southern region). The vigor of seedlings (a qualitative assessment based on the number of vigorous seedlings selected) was enhanced by a good soil water supply during the early nursery stages combined with a higher level of solar-radiation at the nursery site. There was no interaction between the source of seed nut and site of nursery indicating the absence of manifestation of ecological adaptation at the seedlings nursery. The quality of the seedlings was enhanced by adequate soil water and high level of solar radiation on the nursery beds. The subsequent peerformance of these seedlings would have followed up after field planting to confirm the assumptions on adaptation discussed

USE OF RAPDs FOR ESTIMATION OF GENETIC DISTANCES BETWEEN POPULATIONS OF THE COCONUT PALM

Accurate estimation ofgenetic distances between and within species is vital inthe conservation of' heterogeneous tree populations, such as coconuts. Coconutgermplasm is being conserved at present by the selection and preservation ofecotypes and in biased collections that are based on economic traits; suchselections are likely to misrepresent the natural variability ofthe palm. To helpin improving conservation methods, a DNA fingerprinting system, RAPDs(Random Amplified Polymorphic DNAs) is proposed.R4PDs were investigated in 19 coconut types planted at the Coconut ResearchInstitute, Sri Lanka, by using random primers of 10-12 nucleotides. Extracts of'DNA front the leaves (if jour individual trees were pooled to represent eachheterozygotic coconut type. Thirty-eight primers were tested in the RAPD-PC'R*and polymorphic bands and scoredfor presence or absence in each type. Pairwisegenetic distances were calculated according to Nei and Li's coe.fJicient, andcluster analysis was performed on the basis of the resultant distance matrix.Eighteen primers detected a total 91 polymorphic hands across the coconuttypes screened. All these RAPDs were clear and reproducible over repeatedruns. (Trouping of 19 coconut types based on these RAPDs matched thecurrently accepted taxonomic grouping almost perfectly. This good matchindicates that the RAPDs method is applicable as a sound genetic marker fl.lr thecharacterization of' coconut genetic resources. The technique is simple andrapid. It can be developed without previous information about the DNA of thetarget plant. The cost is affordable [or developing countries. The technique isnow widely applied in the breeding and conservation of' heterozygous perennialcrops andforest trees