Evaluation of genetic relationships in Dalbergia species using RAPD markers
Source: Biodiversity and Conservation, Volume 12, Number 2, February 2003 , pp. 197-206(10)
Conservation of identified germplasm is an important component for efficient and effective management of plant genetic resources. Traditionally, species identification has relied on morphological characters like growth habit, floral morphology like flower colour, and agronomic characteristics of the plant. Dalbergia species are important wind-dispersed tropical timber trees which exhibit high intrafruit seed abortion because of intense sibling competition for maternal resources. Studies were undertaken for identification and genetic relationships in five species of Dalbergia and to evaluate genetic diversity within populations of Dalbergia sisso, D. latifolia, D. paniculata, D. assamica and D. spinosa by using random amplified polymorphic DNAs (RAPD) markers. Analysis was started by using 30 decamer primers that allowed to distinguish five species and to select a reduced set of primers. The selected primers were used for identification and for establishing a profiling system to estimate genetic relationships and to evaluate the genetic variability among the individuals in a population of Dalbergia species. A total of 120 distinct DNA fragments (bands), ranging from 0.3 to 4.0 kb, were amplified by using nine selected random decamer primers. The genetic similarity was evaluated on the basis of presence or absence of bands, which revealed a wide range of variability within the species. The cluster analysis indicated that five species of Dalbergia formed two major clusters. The first cluster consisted of D. spinosa, D. latifolia and D. sisso. The second cluster was represented by two species, i.e. D. paniculata and D. assamica. A maximum similarity of 60% was observed in D. paniculata and D. assamica and they formed a minor cluster. Dalbergia latifolia and D. sissoformed another minor cluster with more than 50% similarity. Dalbergia spinosa shared up to 40% similarity with D. latifolia and D. sisso. All the species share more than 20% similarity among themselves. The closest genetic distance existed within populations of different Dalbergia species. Thus, these RAPD markers have the potential for conservation of identified clones and characterization of genetic relatedness among the species. This is also helpful in tree breeding programs and provides an important input into conservation biology.
Document Type: Research article
Publication date: 2003-02-01