The overall efficiency assessment of pot marigold varieties of home and overseas breeding has been studied during the crop vegetation period. Mahrovaya 2000 variety was marked having the best indicators that characterize the inflorescences diameter sign – 5.8 cm, weight of 1,000 seeds is 10-12 g, which is 2.3 cm, higher than the standard and Natalia variety showed the best result – 5.6 cm, weight of 1,000 seeds was 10-12 g, which 2.1cm exceeds the standard.

The seed production rate of one plant, on the average during the two-year period, was manifested in  Mahrovaya 2000 variety with the weight of 1,000 seeds – 10-12 g, which is 15.61 per 1 plant, somewhat lower rate was in the same variety with the weight of 1,000 seeds – 13-15 g, which is 15.4 g per 1 plant. Natalia variety showed the best result with the weight of 1,000 seeds, comprising 7-9 g, i.e. 11.4 g per 1 plant.

The weight of 1,000 seeds varies from 8 to 15 g. It is necessary to take into account that the pot marigold seed weight depends directly on the ratio of seed types in the inflorescence and row number. The weight of 1,000 seeds in non-pleiopetalous  inflorescences with larger curved sickle and shuttles similar seeds is on the average 18 g. In pleiopetalous inflorescences with the overwhelming majority of small annular seeds it is less than 7-8 g. However, the weight of the annular seeds and of other seed types decreases with the increase of double-floweringness. Decrease of the seed size contributes to the increase in the seed number in the pleiopetalous  inflorescences: one  fully double-flowering one has more than 100 seeds, while one non-double-flowering inflorescence has  approx. 30 seeds.

Pot marigold is a strategically important plant in the contemporary medicinal plant production. However, the recent decade has faced the loss of the base of the culture, and consequently the current level of the raw material production does not meet the existing needs of the state.

About 200 species of medicinal plants are used in medicine. Nearly 50 % of them are crop plants.

Herbal medicines tend to have more efficient medical properties than the chemically synthesized agents, and rather often  they are the only medication in the treatment of certain diseases.

The aim of our research was to determine the influence of  1,000-seed weight on the formation of  inflorescence diameter, seed production rate per one plant and the yield rate of pot marigold varieties.

The seed yield properties are characterized by the seed ability to give yield, the size of which is determined by biological inheritance, positive phenotypic plasticity that occurs under the influence of the growing conditions. Various seeds of one genotype (variety), grown in different conditions, in their next generation in the similar growing conditions can give different crop yield. The seed yield properties are used in seed science. Seeds with the high markers of the varietal purity, high sowing qualities and yield properties in case of the appropriate agricultural technology provide high yield rates. While using seeds as sowing material it is taken into account their sowing qualities, i.e. a set of properties that characterize the extent of their sowing suitability (purity, germination and vigor, strength and growth viability, the absence of pests and diseases).

The bud diameter of pot marigold is rather variable as the inflorescence diameter depends on the plant height, plant location shoot order, shoot length, variety, and 1,000 seed weight.

The weight of 1,000 seeds is an important indicator not only for pot marigold but for all the crops. That is why in our research we determined the effect of this indicator on seed productivity per plant.

The production rate is the most important feature of any variety and, therefore, it is usually defined as the main direction in plant breeding. The production rate is the basic indicator, which characterizes the economic value of the variety. The final yield indicator is the result of the complicated interaction of genotype and environment during all the periods of plant vegetation. Yield rate is a complicated indicator, so we should discuss it in terms of a set of properties. In breeding and genetic research works scientists do not examine yield inheritance, but  rather separate signs it consists of. The proper assessment of separate elements of productivity, which influence yield formation, helps achieve the objectives set at the beginning of the breeding process.

Key words: variety, pot marigold (Calendula officinalis), 1,000 seed weight, inflorescence, yield, inflorescence diameter.