The ease with which seeds are detached from the glumes is an important consideration in sorghum breeding, especially in small scale agriculture where threshing is practiced manually. Genotypes with sticky glumes are hard to thresh and the grains have low market value as they are less appealing due to increased proportion of grains with glumes attached. To study the mode of inheritance of this trait, four grain sorghum seed parent lines and eleven grain type pollinators parents differing in the threshability trait were intercrossed in Design ll mating scheme to produce 44 F₁ hybrids. The 44 hybrids and parents were evaluated at Ottawa and Manhattan Kansas in 2010. The experiment was a randomized complete block design with three replications. At maturity, three panicles per plot were harvested. Panicles were weighed and threshed individually. 100 seeds were counted from each threshed head and the number of seeds with glumes attached were counted and used as a basis for scoring threshability. Significant variations for the threshability trait were observed among the entries. Partitioning of the entry effect into parents and hybrids showed both as having significant effect on the trait. Further partitioning of the hybrid into male and female effects again showed that GCA for male and female as being significant with the male effect being apparently more significant.  The male x female interaction was not significant showing that SCA was not important in affecting the trait. SC15 had the highest negative GCA showing poor threshability followed by SC17 and SC21. Likewise, Tx2917 and three other lines had among the highest positive GCA for threshability. Results suggest that additive genes were more important in affecting threshability in sorghum and genotypes with improved threshability can be developed to meet the emerging needs for use of sorghum as alternative food sources and industrial raw material.