Search

The extraction method plays a crucial role in obtaining high-quality DNA samples, which is indispensable for various molecular biology techniques and analyses, enabling a deeper comprehension of genetic information and biological processes. The objectives of the study were: a) to optimize the chloroplast DNA extraction protocol by comparing modified CTAB methods and GeneAid for both leaf and wood samples of Shorea leprosula, a major commercial timber species, and b) to identify a suitable cpDNA region that exhibits variability and universality across taxa. Total DNA was analyzed by gel electrophoresis followed by Sanger sequencing to determine the amplification success. The results revealed that trnL intron, trnL-trnF, and trnG yielded readable sequences of the expected length (maximum 586 bp, 480 bp, and 908 bp, respectively), while the rps 16 intron failed to assemble a contig. The petL-psbE region provided long readability for reverse sequences (769 bp) but not for the forward sequence (195 bp). Higher successful DNA extraction was achieved from the leaves compared to the woods. The lower sequencing quality may be attributed to suboptimal primer design, the structural features of the regions resulting from extensive repetitive sequences, and the suboptimal condition of the extraction method in eliminating wood chemical compounds.

Initial evaluation of phenotypic variability and genetic diversity was conducted on the progeny test of 2 years-old sengon from Solomon provenance, which derived from nine families of mother tree and were then planted in 4 blocks in the Cirangsad Experimental Forest. Phenotypic assessment on eight traits was conducted on 36 trees using a scoring system, while genetic diversity of 15 selected individuals which represented high and low-score phenotypic traits was analyzed using 5 selected RAPD primers. The result on phenotypic assessment showed that family 3 (57.25 points) has the highest average score of phenotypic quality and family 4 has the lowest average score (7.50 points). Furthermore, genetic analysis showed that the low-scoring sengon population had a greater mean genetic diversity (He = 0.2535) than the high-score population (He = 0.2345). The analysis of molecular variance (AMOVA) revealed a significant genetic differences (p-value < 0.001) among high and low-score populations and the dendrogram of genetic distance revealed clustering of individuals having similar superior phenotypic against those having non-superior, indicating the selection based on phenotypes in this study had succeeded in pooling the good quantitative alleles in the selected population. This evaluation results can be used as a reference in determining the best families to produce superior sengon (from Solomon provenance) offspring in the future that have desired adaptability, productivity, and diversity.