Qualities and traits of soybean are reported to produce a considerable variation under conditions of long-day environment (Jaranowski et al., 1980, 1983). An outline of genetic bases for soybean breeding in a latitude above 50°N calls for establishing the least environment-modified traits and relationships. Materials and methods: This study carries a presentation of relationships and heritability of traits in early hybrid generations (F3-F4) from two cross combinations, i.e., a medium-early semi-determinate line (PI 238920) and a somewhat later maturity semi-determinate line (PI 180517) --cross combination "A", in addition to a Japanese cultivar Oyachi No. 2, classified in our conditions to late semi-determinate lines --cross combination "B".