Seed yield components of white clover varieties /Alda, Astra, Owen, Radzikowska/ represented by 10 clones were Investigated in 2-year cycles of field experiments. Differentiation of clones within particular varieties with regard to weight and number of seed per head and 1000 seed weight was determined on the basis of Wricke's ecovalence coefficients. Also the share of genetic and environmental variance in the total variability of the traits under study was determined. It has been found that breeding work contributed to differentiation of yield components and ecovalence coefficients of the varieties tested and their representative clones. A lack of negative correlation between yield structure traits and ecovalence coefficients proved the possibility of improvement of the white clover seed yield stability.