Forest Tree Breeding and Mass Cloning for Tree Improvement in Indian Forestry

Abstract

World-wide activity in forestry shows forest genetics to be the most effective component in tree plantation programs because it produces genetically improved trees that show better growth, tree form, site adaptability, wood quality, crop security and product uniformity. In tree improvement, genetic and silvicultural techniques arc combined at both the nursery-and planting-site-levels (e.g., genotype/site-reactions). The intra-specific genetic variation found within the distributional range of wild tree species forms the basis for selection. This includes provenance, race and plus-tree selection and their site performance evaluations, followed by progeny tests and advanced-generation selective breeding and hybridisation. Genetic control is exercised through seed (sexual) and vegetative propagules (asexual reproduction). Improved germplasm thus produced is multiplied by the tree-breeder through clonal banks, seed zones, seed production areas and seed orchards. Outstanding genotypes are cloned true-to-parent only on a small-scale and mostly to aid breeding through methods of vegetative propagation. Genetically improved plants for plantations are, however, required in large numbers. They can be cloned on a large-scale by developing a tissue culture technique that can produce a large number of genetically stable and uniform trees identical to the elite parent. The situation regarding tree-improvement and mass-cloning research in Indian forestry is discussed with particular reference to the tissue culture technique.