Role of genetics in tree improvement
SA Wani, PA Khan, S Zahoor and ZA Dar
If global warming materializes as projected, natural or artificial regeneration of forests with local seed sources will become increasingly difficult. However, global warming is far from a certainty and predictions of its magnitude and timing vary at least two fold, In the face of such uncertainty, reforestation strategies should emphasize conservation, diversification, and broader deployment of species, seed sources, and families. Planting programs may have to deploy non-local seed sources, imported from further south or from lower elevations, which necessitates a system for conserving native gene pools. Planting a diverse array of species or seed sources is a hedge against the uncertainty inherent in current projections of warming. Most tree improvement programs already stress genetic diversity and deployment of multi-progeny mixes, but may better prepare for climate change by testing selections in an even wider set of environments than is now the case. Gene conservation has three facets: (1) the maintenance of diversity in production plantations to buffer against vulnerability to pests and climatic extremes; (2) the preservation of genes for their future value in breeding; (3) the protection of species to promote ecosystem stability. In practice, economic forces tend to favour genetic monocultures to maximize short term gain. Genes are the raw material from which new strains will be constructed, but only if they are preserved. Tree improvement programs generally promote diversity in seedling plantations to a degree, perhaps, not attained even in natural stands. In high intensity programs, selections from scattered stands are brought together in seed orchards. The progeny, produced by cross pollination, have gene combinations that could never have occurred in nature, where their parents were widely separated. Production plantations established with seed from an orchard of several, say 40, different selections should be in little danger from reduced diversity, especially if the breeding program has been managed to control inbreeding and reduce the chance loss of genetic variability. Even in low intensity tree improvement programs, the genetic base is usually maintained.
How to cite this article:
SA Wani, PA Khan, S Zahoor, ZA Dar. Role of genetics in tree improvement. Pharma Innovation 2019;8(5):63-66.