The aim of the research was to create inbred lines with high combinational ability for use as initial components of newly created synthetic varieties with a regulated genetic basis of the intrapopulation effect of heterosis in panmixia. Methods of research: artificial self-pollination, field testing, electrophoresis of spare proteins, in-vitro, DNA analysis. Results of the research: 100 lines of alfalfa and 50 lines of sainfoin were created by sequential carrying out of induction on genotypes J0, J1, J2, J3 and selection, taking into account the level of self-fertility, to assess their overall combination ability as components of synthetic varieties. The genetic diversity of the infernal line of alfalfa with a variation of H = from 0.245 to 0.422 units was established, and in the sainfoin line with a variation of H = from 0.245 to 0.274 units. The sainfoin lines (E-4230 and E-2236) and alfalfa (D-19/24, I-6/33, D-8/33) are characterized by the greatest genetic diversity. The genes of inbred lines have a partial similarity both in the spectra of seed storage proteins and in the amplified DNA fragments of the SSR type of markers. Of the 1,240 polycross progenies from the infernal line of alfalfa, 58 lines with a competitive heterosis rate of 20-30% and, accordingly, on a sainfoin of 486 polycross hybrids - 15 with a competitive heterosis rate of 15-24%, were singled out for general combining capacity. Microclonally propagated 2 valuable inbred lines of alfalfa -C-21/14 and K13 / 07 with the production of clones of 1566 pieces, as well as 2 valuable inbred lines of sainfoin -E-2247 and E2269, producing clones of 787 pieces. On 30 lines of alfalfa and 15 sainfoins, hybrid seeds are harvested in sufficient quantities from polycross nurseries to assess their overall combinational ability