Rapid advances are being made in the field of plant biotechnology, and an already immense literature on the subject is expanding exponentially. Biotechnology is becoming a major tool in the genetic improvement of many crops- micropropagation is the basis of a large horticultural industry, anther culture is important in the breeding of some cereals, a few crops genetically engineered for insect and virus resistance are at or near commercial deployment, and molecular markers have assisted in the breeding of tomato.
Biotechnology is being applied also to the urgent problem of improvement of crops in developing countries, and many biotechnology networks and training programmes are in place (Izquierdo & Villalobos 1992, Roca & Thro 1992, several articles in Persley 1990). Forestry problems in many developing countries are no less acute, and it has been suggested that biotechnology may offer solutions to these.
Tree improvement activities typically comprise:
Practical tree improvement operations - species and provenance testing, establishment of gene conservation and breeding populations, recurrent cycles of selection and recombination, and propagation of selected lines (e.g. open-pollinated families or clones).
Supportive research - essential to run a breeding programme effectively. This includes the examination of factors such as breeding biology, mating patterns, genetic parameters (including variation) and seed problems.
Strategic research - aimed at the development of better breeding methods, e.g. through early selection.
While biotechnological projects currently constitute a substantial component of strategic research, practical breeding operations are largely conducted using traditional methods. Potential applications of biotechnology in the improvement of forest tree species have been discussed in many reviews (e.g. Sederoff & Ledig 1985, Dunstan 1988, Riemenschneider et al. 1988, Kriebel 1989, Krugman 1990, Cheliak & Rogers 1990, Kleinschmit & Meier-Dinkel 1990, Haggman 1991, Huang et al. 1993). While biotechnologies are expected ultimately to constitute supplements, and sometimes alternatives, to traditional methods now used in breeding programmes, clearly there still exists a wide gap between biotechnology and traditional methods. It has been suggested (DeYoe & Scowcroft 1988) that silviculture “lags far behind agriculture and horticulture in its willingness to pay the price for technological innovation”. On the other hand, Sedgley & Griffin (1989) suggest that breeding programmes in both forestry and horticulture are being sacrificed in favour of biotechnology programmes. This analysis is therefore aimed at the characterization of the gap between biotechnology and traditional methods in tree improvement programmes, in particular those in developing countries, through the following:
Review of the status of forest tree improvement.
Review of the status of relevant biotechnologies.
Evaluation of areas in which technology might be complemented or possibly replaced, in the near future, in operational breeding and supportive research activities.
Prioritization of biotechnological strategic research objectives.
Biotechnology has been defined broadly to include “any technique that uses living organisms, or parts of organisms, to make or modify products, to improve plants or animals, or to develop micro- organisms for specific uses” (Persley 1990). The analysis presented here is restricted to “modern” biotechnologies for which application in plant improvement has at times been envisaged. The technologies included are: cryopreservation and in vitro storage; use of molecular markers; in vitro selection; genetic engineering; use of somoclonal variation; protoplast fusion; haploid cultures; in vitro embryo rescue; micropropagation; and in vitro control of the maturation state. Omitted or considered only in passing are applications not directly related to genetic improvement of the crop, for example: biotechnological approaches to the study of symbiotic microorganisms; biopulping and biobleaching; fermentation of wastes; and the in vitro production of products currently harvested from trees, e.g. the anti-cancer compound taxol (Ellis et al. 1992). Omission is not meant to imply that these are not useful research directions.