Genetic diversity of putative wild-type coconuts (Cocos nucifera L.) and their in situ conservation in Eastern Samar and Surigao del Norte, Philippines
2006
Catibog, N.A., Philippines Univ. Los Baños, College, Laguna (Philippines)
The putative wild-type coconut populations documented by Gruezo and Harries (1984) in Eastern Samar and Surigao del Norte were studied to determine their genetic diversity using morphological characters and microsatellite markers. Likewise, the status and causes of genetic erosion and different indicators associated with on-farm conservation were assessed. Moderate diversity exists in the putative wild-type coconut populations based on qualitative and quantitative morphological characters. The first three principal components accounted for 98.2% of total variation. PC1, composed of vegetative and reproductive characters, was responsible for 80.3% of the variation, the highest of which was contributed by the rachis length. Morphological characters effectively distinguished the putative wild-type coconut populations from the domesticated populations based on cluster analysis. Low diversity was recorded in the putative wild-type populations using 7 SSR primers. In terms of allelic richness, these populations were more varied than the domesticated populations. Seventeen putative could be prime candidates for conservation. There is a need, however, to screen and use additional primers to distinguish more effectively between domesticated and putative wild-type populations. Coconuts, in general, are not in immediate threat of genetic erosion in the areas studied. On the other hand, 73.4% of the total putative wild-type population in 1984 has been lost, indicating a very serious case of genetic erosion. They have very low economic utility and may soon be replaced with other varieties.
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