Anatomy of Seed Dispersal Mechanisms in High and Low Seed Shattering Cultivars of Orchardgrass

To obtain information for breeding improvement programs in seed retention, the mechanism that leaeds to seed shattering in orchardgrass was histologically determined in two cultivars, Hallmark and Marta, chosen for their different shattering levels. Two abscission layers were identified in both cultivars at the first stage of floral development. A primary abscission layer was located in the rachilla supporting the fertile floret; a secondary layer extended across the pedicel near the base of the glumes