STRUCTURAL ANALYSIS AND SEED PRODUCTIVITY OF POPULATIONS OF BIRD'S FOOT TREFOIL GROWN UNDER CONDITIONS OF CENTRAL NORTHERN BULGARIA

During the period 20016-2018 in the experimental field of RIMSA-Troyan were tested selection populations of bird's foot trefoil Syn(1), Syn(2), Syn(3), Syn(4), Syn(5), compared with to the Bulgarian variety 'Targovishte 1'. Seed yield and its structural elements were determined in the second and third years of the development of grassland and on the basis of studied reproductive indicators interrelations among them and productivity were established It was found that the maximum yield of seeds was obtained by the population Syn(1) - 0.37 t.ha(-1), with an excess over the standard by 23.73%. High productivity is determined by the large number of seeds per pod (18.6). The lowest degree of variability according to the variation coefficients was found in the number of racemes per stem (5.89), and the highest in the number of pods per plant (19.40). The established very strong correlation between the number of pods per raceme and the weight of 1000 seeds (r = 0.7939). allows to derive the regression equation - y = 0.0794x + 0.9588. Thus, the presented statistical analysis of the data from the seed productivity allows to make a complete characterization of the populations, which will serve for the further selection process.