Articles
INTRODUCTION : HORTICULTURAL BIOTECHNOLOGY: A HISTORICAL PERSPECTIVE AND FUTURE PROSPECTS
In 1934, P. White established an ongoing in vitro culture of tomato roots in liquid medium, and in 1939 R. Gautheret initiated the first long-term callus culture from carrot explants.
Both types of culture exhibited an unlimited ex-planta cell division and growth, surviving many axenic subcultures on defined nutrient media.
The basic in vitro studies involved first two vegetable crops, and since then the technology is serving the entire horticultural industry in three major areas: (1) clonal, large-scale commercial micropropagation, (2) improving the breeding efficiency and shortening the breeding cycle, and (3) as an aid in studying plant development and physiological aspects.
Historically, as judged by the success of transferring laboratory results to actual commercial application, micropropagation of flowering and ornamental plants was the first (both for large-scale clonal propagation and production of pathogen-free stocks), followed by some vegetable crops (mainly for elimination of viral and bacterial diseases), and only later for fruit trees and plantation crops (for virus elimination, commercial clonal and rootstock propagation). The application of in vitro culture to horticulture for improving breeding efficiency became a practical reality only later.
This includes introduction of in vitro techniques for embryo rescue, haploid generation from pollen, for somatic hybridization and selection via protoplasts, for mutant induction and selection in cell cultures, and more recently for generation of transgenic horticultural plants with improved traits.
In fact, most, if not all, of the molecular genetic techniques of plant improvement, especially the production of transgenic plants, rely on selection and regeneration of plant cells and tissues in culture.
Both the basic and the applied aspects of horticultural biotechnology are intimately associated with manipulation of cells, tissues and organs in culture.
In the following, a brief appreciation of the achievements and future prospects of in vitro culture in micropropagation and breeding of horticultural plants is presented.