The subspecies Subrhomboideus (Rydberg) Heiser of the perennial hexa ploid species Helianthus pauciflorus (rigidus) was crossed with the cultivated sunflower H. annuus L. The crossability rate was high. Seeds and hybrid plants were obtained in both directions of crossing. The F1 plants had an inter mediate type of heritability, but they strongly resembled the wild parent in most important biomorphological characters. All plants were with the peren nial cycle of growth. During the second and third years, a large number of plantlets emerged from sleeping buds on the root system of F1 materials. The hybrid nature of the F1 plants was confirmed through cytological, RAPD and electrophoretic analyses of seed storage proteins. Polymorphism of H. annuus, H. pauciflorus ssp. subrhomboideus and theirs F1 hybrids was studied by RAPD. The results showed introgression of the subspecies Subrhomboideus in the hybrid progeny. It was established that the subspecies carried Rf genes for cms Pet-1. As a result of self-pollination, sib-pollination and back-crossing to cultivated sunflower, F2, F3, F4 and BC1 progenies were obtained. Some of the obtained hybrids were included in a program of development of lines for heter osis breeding in sunflower.