1. Micro- and macro-propagation

Tissue culture methods for bamboo, eucalypts, phyllodenous acacia, neem and teak mass multiplication were established, and clonal plantations were popularised through on-site demonstration trials. Quality planting material of tissue culture teak, Casuarina hybrids, Eucalyptus, Cadamba and Melia dubia are multiplied vegetatively and supplied to the Forest Department, farmers and industries.

2. Molecular genetics and genomics research

Diversity analysis and genomic selection in teak: Superior selections of teak were sampled for morphometry, wood metabolites and genomic analysis. Results revealed the presence of wide variation across populations for heartwood content and wood chemicals, as well as at the genomic level. SNP markers identified at the chromosome level and will be applied for marker-trait correlations following GS models.

Timber Forensics: A novel barcode to discriminate red sanders from other Pterocarpus species was developed through a plastome skimming strategy and was validated in seized timbers. Further, a high-quality reference draft genome of P. santalinus was generated, and whole-genome resequencing revealed the presence of two genetic clusters in the species. Fourteen samples from seized wood were subjected to whole genome re-sequencing followed by an assignment test to identify the origin of the seized timbers.

Gender-linked polymorphisms in Calamus brandisii: The first comprehensive comparative genomics study was conducted between the male and female genomes of C. brandisii to identify polymorphisms and potential genes for gender determination. Comparative analysis revealed significant genetic variation between the two genomes. A total of 5 male-specific and 11 female-specific genes linked to the gender-determining region were predicted. The genomic variants identified between the two genomes could be used in the development of markers for early gender identification in C. brandisii for restoration programs.

3. Genetic modification and genome editing research

The tree genome engineering programme aims to develop climate-resilient trees with improved wood traits.

• Methods for the generation of transgenic (both whole plant and composite), gene-silenced and gene-edited Eucalyptus were developed.

• The MsPRP2 promoter was identified to direct transgene expression preferentially in callus, roots, xylem and phloem, and leaf veins of Eucalyptus.

• The promoter was also used for directing CRISPR/Cas-mediated deletion of 1412 bp in the EcHKT1;1 gene of Eucalyptus.

• The synthetic NaKA and ClC genes from the halophilic crustacean animal, Artemia, directed by the MsPRP2 promoter, were expressed in the roots of Eucalyptus composite transgenics to evaluate for enhanced salt tolerance.

• Further, potential genes conferring salt tolerance in the salt-loving mangrove species of Rhizophora were identified by differential transcriptome analysis.

• EcHKT1;1 gene-silenced Eucalyptus RNAi transgenics were generated and used as rootstock to develop transgrafts.

The advances made in these areas have enabled initiating projects on engineering faster growth, improved pulping traits and bioproduction of commercially valuable secondary metabolites in Eucalyptus and Sandal.