Backcross breeding to increase seed retention in cocksfoot (Dactylis glomerata L.)

Summary The objective was to evaluate the effectiveness of the backcross breeding method to improve an existing variety (Hallmark) for higher seed retention.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.