Abstract
The paper presents the evaluation of the total combining ability of the seed parents of white sweet clover Melilotus albus and yellow sweet clover Melilotus officinalis based on leaf formation, forage productivity and seed productivity. The results of competitive heterosis for the yield of herbage, dry matter and seeds of the polycross offspring Syn1 are also presented. Among the polycross offspring Syn1 Melilotus albus, SGP-4-12507 and SGP-5-12508 were selected based on their leaf formation (50 and 50%, respectively); competitive heterosis was 16.3 and 22%, respectively. Based on the total combining ability of offspring Syn1 of Melilotus albus, the following biotypes were selected: SGP-2-12519 (27.1%) and SGP-1-12503 (20.8%) for forage productivity; SGP-4-12601 (14.7%) and SGP-5-12508 (13.0%) for dry matter productivity; SGP-4-12601 (50.4%), SGP-2-12519 (19.2%) and SGP-5-12508 (14.1%) for seed productivity. The highest total combining ability were found for the following biotypes of Melilotus officinalis: SGP-9-12454 and SGP-10-12455 for leaf formation (18.2 and 13.3%, respectively); SGP-10-12455 (12.5%) for herbage productivity; SGP-10-12455 (29.6%) and SGP-9-12454 (24.2%) for dry matter productivity; SGP-6-12520 (15.4%) and SGP-9-12454 (14.1%) for seed productivity. Selected sweet clover samples can be recommended as the best basic material for further work on selection for high forage and seed productivity.