Abstract. For determination of the plant height, number of main stems and productivity of varieties and populations birdsfoot trefoil a field experiment was carried out during 2008-2010 period in RIMSA – Troyan. Objects of study were the populations originating from: Shumen, Nesebar, Kiten, Tryavna, Sadovo, as well as genotypes of the varieties: V. Podolyanskii (Russia), Dedinovskii (Russia), Martanskii (Russia), Zora (Serbia), Bokor (Serbia), Smolenskii (Russia). Variety Targovishte 1 (St) was used for comparison. The aim of this study is was to investigate the biometric and quantitative indicators of birdsfoot trefoil varieties and populations under agro-ecological conditions of Troyan. The highest forage productivity was obtained in variety Dedinovskii, under the soil and climatic conditions of Troyan. The variety was characterized by high stems and the highest number of main stems. The populations originating Nesebar and Kiten also realize high productivity. The lowest productive was obtained in the variety Zora, due to its poor adaptability to specific soil conditions and lower its productive potential. The third year of the experimental period was characterized by rather high productivity of all studied accessions. The average height of all varieties and populations was 25.4 cm, with minimum and maximum 22.5 cm 29.2 cm. According to the variation coefficient values of the indicator stem height (CV=6.73%) was set very low variability. Average for the period of the investigation the values for the number of main stems varied from 23.7 to 44.0 and their maximum was observed in a variety Dedinovskii (44.0), Martanskii (37.7) and population Nesebar (37.0). The higher density of these accessions and explains their higher productivity.
Key words: birdsfoot trefoil, varieties and populations, plant height, number of main stems, productivity