Relevance. Basil is one of the most popular aromatic plants grown in the world. Various species and forms of Ocimum spp. differ in the nature of growth, color and aromatic composition. The VIR basil collection is represented by 452 accessions of six species from 55 countries. The expansion of the assortment of basil, as well as the identification of competitive adaptive cultivars with high economically valuable traits, determines the need to study and identify promising species and forms of Ocimum spp. The purpose of our work was to study accessions of basil (Ocimum basilicum) from the VIR collection by morphological and phenological traits and to identify accessions that have a complex of economically valuable traits for further use in the breeding.Materials and methods. The studies were carried out at the Federal Research Center N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) at the VIR Pushkin and Pavlovsk Laboratories in 2019-2021 in open ground conditions. The material of the study was 66 accessions of the VIR basil collection of various agrobiological status and ecological and geographical origin. When analyzing the material, phenological observations, biometric measurements and morphological description of plants were carried out. These measurements were carried out in the phase of mass flowering.Results. As a result of the study, the degree of variability of the main phenological and morphological features was revealed. Accessions of basil were selected according to such traits as early maturity, plant height, weight of one plant and cold resistance, which can be used as starting material for breeding. The studied accessions are grouped into 7 varieties of two subspecies (subsp. basilicum and subsp. minimum): var. basilicum, var. glabratum, var. purpurescens, var. majus, var. diforme, var. minimum and var. chamaeleonicum, and their characteristics are given.

Selenium accumulation level in basil plants is investigated. A direct correlation between selenium concentration and essential oil content is demonstrated for basil and other aroma plants. No correlation is found between selenium and flavonoids.

Ocimum basilicum L. (common basil) is one of the promising spicy - aromatic and medicinal plants. It is used both in traditional and traditional medicine as an expectorant, anti-inflammatory agent, gastritis, colitis, nephritis, etc. Numerous scientific studies have established that O. basilicum L. essential oil in experimental practice has good antioxidant, antimicrobial, and cytostatic activity. The modern spice market requires a growing variety of forms and varieties of basil for consumption as seasoning and green vegetables. An important place is occupied by raw materials (leaf and herb of basil), in recipes of medicinal and forest teas. Essential oil is used both in the food and in the perfumery – cosmetic industry and pharmaceuticals. Perspectivity in the spice market and its multiple medicinal properties were the reason for the continuation of work on the improvement and creation of new promising varieties of basil, of various uses. A working collection was created, consisting of 34 varieties, forms and nursery of crosses and breeding selections, numbering from 40 to 100 units, on average by year. Five varieties of basil of diverse directions were created and registered in the State Register, both for consumption as seasoning in fresh and dry form, for flavoring edible salt, vinegar and oil, and also as a medicinal raw material for teas. Brief results obtained over 17 years а presented in this paper.

Essential oil crops and their essential oils are widely used in perfumery, cosmetic and food industries, traditional and folk medicine. The most important qualitative characteristic of essential oil crops is the content, component and enantiomeric composition of essential oils. Basil (Ocimum basilicum L. and Ocimum tenuiflorum L.) and hyssop (Hyssopus officinalis L.) belong to the promising essential oil crops for cultivation in the soil and climatic conditions of the Republic of Belarus. In the Belarusian State Agricultural Academy has created a number of varieties of essential oil crops, including 3 varieties of basil Ocimum basilicum L., 1 variety of basil Ocimum tenuiflorum L.) and 1 variety of hyssop Hyssopus officinalis L. The new varieties of basil and hyssop are characterized by a complex of morphometric, morphological and phenological sings.In the studies of the Belarusian State Agricultural Academy and the Belarusian State Technological University, the yield and content of essential oils of new zoned varieties of basil and common hyssop were analyzed. Using the method of enantioselective gas chromatography, the component and enantiomeric composition of essential oils of the studied varieties was determined. As a result of the research, it was determined that each variety has its own characteristic component and enantiomeric composition of essential oils. The studied varieties of basil and common hyssop contained up to 20 and 18 different components of essential oils respectively. The features of the component and enantiomeric composition of essential oils allow identifying the already created varieties of essential oil crops, as well as carrying out their selection to create varieties with certain properties.