NATIONAL BOTANICAL GARDENS

Director and Chair of the Scientific Council Dr.biol. K. BUIVIDS

Founded in 1956 as LAS Botanical Gardens, but in 1992 it has been granted the status of National Botanical Gardens. During the forty years of its existence the richest plant collection in the Baltic states has been gathered there. About 10-12 thousand plant taxa, species, subspecies, and forms have been gathered and maintained as well as 5-6 thousand varieties. Separately at the arboretum more than 5 thousand tree and shrub taxa are to be found. The collections are specialized. Many genera have national, but some (Crataegus, Cotoneaster, Populus, Allium, etc.) collection-significance of world scale.

Main Areas of Research

• Dendroflora of Latvia (the Baltics). Studies of the acclimatization and systematic correctness of newly introduced tree and shrub varieties and decorative forms have been made. Descriptions of the protected trees and shrubs and their distribution maps have been prepared for the new edition of the Red Data Book of Latvia. More than 200 thousand of big trees have been inspected, measured, and registered in the computerized database. The inspection and evaluation of Latvia's protected country parks is continuing, a database has been evolved. Another database, "Plants of the NBG", is under preparation. Vegetative propagation methods for coniferous and deciduous trees, shrubs, and climber plants have been developed, by applying biologically active substances produced in Latvia. The culture of larch trees growing in Latvia has been evaluated, and recommendations worked out for their improvement. Experimental plantations of fast growing poplar clones are being made for afforestation of lands not suitable for agriculture. In three regions of Latvia the biomechanical and physiological changes of some clones of the Scotch pine tree have been studied (chlorophyls, carotinoids, and macroelements) depending upon the soil, contamination of the environment, and the physiological condition of the plant. Preservation and propagation of the protected plants of Latvia has been made.

• Breeding. Evolvement of new breeding and propagation methods. New forms of decorative plants (gerberas, chrysanthemums, orchids, astilbes, hostas, bulbous plants, et. al.), many cultures of berry plants (black currants, blueberries, cranberries, cowberries, mountain ash, and others), decorative trees and shrubs (park roses, bush roses, climber varieties of Rosa rugosa, and others), interior plants as well as turf grasses. While continuing studies of the reaction of different genotypes to lowered temperature and lighting, four forms of gerberas and 13 forms of chrysanthemums have been singled out as relatively tolerant. Work on obtaining inbredlines for gerberas (10 lines) has been continued, the regularities of inheriting their colour and forms have been clarified. The combinating ability of the plants of these lines has been defined as well as the possibilities of their use in further selection. Large efforts have been devoted to the maintenance of taxonomically correct and corresponding to phyto-sanitary requirements of the national chrysanthemum collection (280 taxa) and collection of gerberas (200 taxa). These collections are the only ones in the Baltics. Four varieties of gerberas and six of chrysanthemums have been registered in the State Variety Register.

• Berry plants. The genofund of these plants as well as the plant bank in vitro (76 forms) has been enlarged. Perspective hybrids of cowberries and blueberries have been selected and propagated. Large fruit cranberry forms have been obtained, their productivity by 23-27% surpassing the North American varieties. By interspecific hybridization, selection, and backcrosses 11 black currant forms have been obtained especially productive and can be gathered in by mechanized methods. They will be registered as suitable for technical purposes.

• Turf grasses. Three red and chewing fescues forms have been singled out as perspective for Latvia and the Baltic as well as two forms of Kentucky bluegrass. Criteria for evaluating turf grasses of distinctive functions have been worked out (NBG, Priekuli Plant Breeding Station, Institute of Agriculture).

• Plant tissue cultures. The largest active plant bank in vitro in the Baltics contains more than 350 plant taxa from 40 genera, including Latvia's selectionist varieties. Conservation methods of the genofund have been developed and perfected. The influence of prolonged cultivation in vitro on plants has been studied. Programmed propagation of tree plants has been worked out, including the balance of active substances, contents and proportions of minerals, explant treatment substances, and storage regimes. The suitability of preparations produced in Latvia in the tissue cultures of various plants has been studied. The 2nd international symposium "Breeding, Propagation in vitro, and Disease Resistance in Horticultural Plants" (April 16-18, 1996) was organized and its materials published.

By marking the 40th anniversary of the NBG an international conference "The Role of Botanical Gardens in Plant Acclimatization, Horticulture Science, and Practice" (September 3-4, 1996) was organized.

Collection of articles "The Baltic Botanical Gardens in 1994-1995" was issued.

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