The recurrent parent was cv. Hallmark (H) and the donor parent was cv. Marta (M). Marta is an Italian cultivar with a high degree of seed retention. Two cycles of backcrossing with selection for higher seed retention were conducted. In each cycle, 1200 plants were grown. In both BC₁ F₁ and BC₂ F₁, 20 plants were selected for general features of H and for a high degree of seed retention. The 20 plants of BC₂ F₁ were intercrossed in 1989. The bulked population thus obtained (HS) was evaluated in 1989–90 together with H and M as spaced plants in a randomized complete block design with 4 replicates. Regarding seed retention, H had a score of 7.9, M of 1.7 and HS of 2.8, LSD (0.05)=0.8, on a scale from 1 to 9. Consequently HS had similar seed retention to M but similar ear emergence date, plant height and panicle morphology to H. The results confirm that seed shattering is under control of a single partially or completely dominant gene.