Genetic Base and Improvement:

About 90 percent of the poplar plantations in India are based on clones G-48, D-121, S7C15 and G-3. The yield of clone G-3, which once used to be the most popular clone, is declining due to attack by leaf blight disease. This clone is giving way to other clones, e.g., S7C8, Uday, L-34/82 etc. Individual plantations are, however, monoclonal (Kumar et al, 1998).

To increase the productivity of poplar, FRI Dehradun started a National Poplar Improvement Programme in 1997. Salient achievements of this initiative are:

(i) Clones of poplar introduced in India since late-1950 were ranked on the basis of volume growth. Clones S7C8, 82-35-4 and 113324 were found to give higher yield than G-48, presently one of the most popular clones in agroforestry plantations. Based on these rankings, a vegetative multiplication garden was established at FRI, Dehradun to supply cuttings of superior clones to growers.

(ii) Multilocation field trials of best 60 clones of previous introduction have been established at about 30 sites throughout the traditional as well as potential zones of poplar cultivation covering Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana, Uttar Pradesh, Bihar, West Bengal, Orissa, Chhattisgarh, Maharashtra, Gujarat, etc. Fifteen Research Institutions comprising Universities, State Forest Departments are collaborating with FRI, Dehradun in this programme.

(iii) Intraspecific hybridisation amongst best 40 clones has been carried out. 289 clones from control-pollination and 111 clones from open-pollination have been selected for field trials.

(iv) Seed from 104 candidate plus trees growing in 44 natural stands in the USA has been brought to FRI Dehradun. 100 clones have been selected out of the new germplasm for further trials (Singh et al,2003).

(v) A new approach of multi-step selection and concurrent multiplication has been developed at FRI Dehradun which enables multiplication of germplasm of superior clones at 2 years of age while clonal trial is stilI underway. This reduces the time period in clonal testing and multiplication process by 4

years (Kumar and Singh, 2000).

(vi) Hybrid seedlings of P. deltoides 'G-48' x P. euphratica have been produced to combine the rapid growth of P. deltoides and stress tolerance of P. euphratica (Singh et al, 2003)

WHAT ARE HYBRID CLONES?

A hybrid is a cross between two distinct species. The main eucalypt species we are interested in for Uganda are E. grandis (G), E. camaldulensis (C) and E. urophylla (U). E. grandis is nearly always the mother tree in the hybrid crosses. The two

hybrids we are most interested in are GxU and GxC – hereafter GU and GC. Some of the GU and GC hybrids combine the best traits of each parent and it is the best of these that we want to copy – or clone. Clones are plants produced vegetatively

(i.e. asexually) from a common ancestor. The most common method is by rooting cuttings from the parent tree. All the cuttings produced from one parent are genetically identica

Commercial uses of Eucalyptu

·         Eucalyptus is one of the fastest growing trees and is an excellent timber for paper and pulp, particleboard and hardboard industries.

·         It is also an excellent source of fuelwood and charcoal.

·         Eucalyptus wood is also used for light and heavy construction, railway sleepers, bridges, piles, poles and mining timber.

·         Indian Standards are available for use of E. tereticornis timber, after treatment, for door frames, window shutters, furniture, cabinet, tool handles, packing cases and crates.

·         Leaf extracts of the species have pesticidal properties and can be promoted as a biopesticide.

·         The leaves of the species are rich in essential oils, that have many medicinal uses. Eucalyptus globulus can be raised commercially for Eucalyptus oil.

·         E. tereticornis is a major source of pollen in apiculture and produces a medium amber honey of distinctive flavour.

·         The wood and bark of the tree have a tannin content of 6-12% and 3-15% respectively, though not used as a commercial source of tannin.

·         Eucalyptus is a large ornamental tree suitable for parks and avenue plantations.

·         The tree may be used as an agro-forestry species. Eucalyptus in combination with pineapple have given excellent results in China.

The tree species can be effectively used for regeneration of denuded lands and prevention of soil erosions in drought -affected areas.