Biology subjects

Vaishnav, V.

Publications and source records attributed to Vaishnav, V..

4 recordsLinked to original sources

bioRxiv2022

Genetic variation associated with relative resistance in teak (Tectona grandis L. f.) against the leaf skeletonizer, Eutectona machaeralis Walker

BackgroundPhotosynthesizing tissue of teak (Tectona grandis L. f.) foliage is damaged by a host-specific insect pest called leaf skeletonizer (Eutectona machaeralis Walker) that severely eclipses annual growth increment and carbon sequestration of natural populations and plantation of teak. Gene-assisted selection of relatively resistant teak clones may efficiently control the damage in the populations and plantations. The present investigation aimed to identify genetic variation associated with relative resistance in teak against the pest. MethodThe investigation was carried out on 106 teak plus tree clones assembled at the National Teak Germplasm Bank from the Indian meta-population of teak. Resistance data were obtained recording the ocular damage caused by the pest to teak accessions for four years. Genotyping of the teak accessions was performed with 21 co-dominant markers and marker-trait association mapping was performed confirming the genetic structure of the germplasm bank and linkage disequilibrium (LD) among the marker loci. ResultsThe sampled teak accessions exhibited a low albeit highly admixed genetic structure (FST=0.07) and low level of LD (16.66%) among loci, making them suitable for high-resolution association analysis. A significant correlation (p[≤]0.01, R2=0.67) was obtained between intra-specific heterozygosity and the relative resistance against the pest. A marker locus CCoAMT-1 representing the enzyme caffeoyl-CoA O-methyltransferase of phenylpropanoid pathway was also found significantly (p[≤]0.05) associated with the relative resistance against the pest explaining 6.6% of the phenotypic variation (R2=0.066) through positive effect (0.57) on the trait. ConclusionsThe present work exhibited a significant correlation of intra-specific heterozygosity with relative resistance in teak against a pest. It is the first report on teak identifying genetic markers associated with relative resistance against the pest. The marker can be applied for the selection of resistant planting stock for breeding and commercial plantation. Further investigation can be performed to understand the expression level polymorphism linked with the resistance applying next-generation sequencing approaches.

plant biology↗

bioRxiv2022

Ecology and Conservation status of Phoebe hainesiana Brandis: a data deficit timber species of Indo-Myanmar biodiversity hotspot

Phoebe hainesiana Brandis (Lauraceae) is an economically significant timber yielding forest species endemic to North-East India in Indo-Myanmar Biodiversity Hotspot (IMBH). The tree exhibits significant commercial importance in timber industries due to its peculiar wood qualities. The timbers strength, toughness, and durability make it in high demand for furniture making. Despite its significance, the botanical description of the species is not well documented due to the confined distribution of the species in IMBH region. The natural population is rare, but it is the least concerned species in the IUCN Red List. Moreover, no taxonomical description of the species is available for its distinct identity among the other species from the genus. In the present study, we conducted a taxonomic, ecological, and forestry assessment of the species in its natural environment, researching the literature and conducting a field survey. A significant variation in intra-specific wood density (450 kg/m3 to 800 kg/m3) determines the scope of robust selection for the genetic improvement of the species. Its population has been severely fragmented due to over-harvesting in lack of sustainable management. According to our findings, the species is endangered due to a rapid decline in its population, a limited extent of occurrence, and a small area of occupancy. Among the other four species from the genus found in India, P. hainesiana can be identified based on its distinct lobes of the fruiting perianth. We recommend a sincere effort for the conservation of this key species of tropical evergreen forest in IMBH region.

plant biology↗

bioRxiv2018

Comparison between QST and ΦST indices in an endangered Boswellia serrata Roxb: Implications for conservation

Boswellia serrata, an economically important indigenous tree of dry deciduous forests, provides oleoresin gum of pharmaceutical significance and excellent pulp for paper industries, but faces threat to extinction due to poor natural regeneration and commercial exploitation. 240 individuals of the species representing 12 locations of its natural distribution in central India were investigated to compare the genetic differentiation indices, QST for GBH and wood fiber length and {phi}ST for neutral (RAPD+ISSR) markers. The comparison for paired locations was more informative than for metapopulation. The most paired locations were either under the stabilizing selection (QST (L) < {Phi}ST (L)) or in the genetic drift (QST(L) = {Phi}ST (L)) whereas a relatively small number of paired locations was under the divergent selection (QS T(L) > {Phi}ST (L)). The comparison for the metapopulation generating only a single trend of QST (P) > {Phi}ST (P) is, therefore, misleading. For conservation, the genetically deficit locations (QST (L) < {Phi}ST (L) and QST (L) = {Phi}ST (L)) of B. serrata warrant for reinforcement of their genetic diversity by introduction of genotypes from other genetically divergent locations (QST (L) > {Phi}ST (L)), which would check the fragmentation and genetic drift, resulting in reproductive vigour, natural regeneration and reverse the endangered status of the species.

genetics↗

bioRxiv2018

Assessment Of Genetic Structure Of The Endangered Forest Species Boswellia Serrata Roxb. Population In Central India

Boswellia serrata Roxb., a commercially important species for its pulp and pharmaceutical properties was sampled from three locations representing its natural distribution in central India for genetic characterization through 56 RAPD + 42 ISSR loci. The wood fiber dimensions measured for morphometric characterization confirmed 11.36% of the variation in the length and 8.75% of the variation in the width indicating its fitness for local adaptation. Bayesian and non-Bayesian approach based diversity measures resulted moderate within population gene diversity (0.26{+/-}0.17), Shannons information index (0.40{+/-}0.22) and panmictic heterozygosity (0.28{+/-}0.01). A high estimate for genetic differentiation measures i.e. GST (0.31), GST-B (0.33{+/-}0.02) and {theta}-II (0.45) led to the distinct clusters of the sampled genotypes representing their regional variability due to limited gene flow and total absence of natural regeneration. We report the first investigation of the species for its molecular characterization emphasizing the urgent need for the genetic improvement program for the In-situ/Ex-situ conservation and sustainable commercialization.

plant biology↗