To make clear the difference among strains and heritability for the rutin content in seed and leaf of tartary buckwheat, sixteen strains introduced from main cultivating countries were grown in 1992 and 1993 with 2-replicated randomized block design, The rutin content in seed and leaf were determined by means of the high performance liquid chromatography (HPLC), Three main characters were also observed, The seed rutin content was observed from 1,110 to 1,950 mg/100 g DW, The leaf rutin content varied between 2,460 and 3,610 mg/100 g DW. By the analysis of variance, the significant differences among strains were recognized in the seed and leaf rutin content, The estimated heritability values of the seed rutin content and the leaf rutin content were 0.76 and 0.10, respectively, The heritability of the seed rutin content was as high as that of the days to first flowering, To clarify the effect of individual selection on the rutin content, the parent-offspring correlation analysis for seed rutin content was carried out, The correlation coefficients of the rutin content between the parent individuals and the progeny lines were nearly zero, Therefore, most of the phenotypic variation among the parent individuals was due to the environmental variation, This indicates that enlargement of genetic variation within a strain through crosses between strains or mutagen treatments is necessary for the breeding of the seed rutin content by individual selection in a tartary buckwheat strain, On the other hand, heritability of the leaf rutin content is relatively low in comparison with those of the main characters.