The study was conducted in the period from 2014 to 2021 in the experimental field of the Institute of Forage Crops - Pleven, Bulgaria. As a result of purposeful scientific activity at the Institute, new varieties of the grass pea were created, as well as promising lines of this crop in the direction of grain production. The study aimed to investigate the breeding and genetic possibilities for enriching the genetic diversity of the grass pea by the methods of combinatorial breeding. Morphological, ecological and biochemical assessment of the collection samples from grass pea was done. The phenotypic correlations between the main features of this species have been determined. Breeding and genetic research has been carried out and the ways of inheriting economically valuable quantitative traits in hybrid generations have been studied. Dominant to hyperdominant negative inheritance was found in F1 at BGE027129xLA5108 for fresh root weight, aboveground biomass weight and nodule weight; LA5108xBGE027129 by fresh leaf weight and aboveground biomass weight.