To shatter or not to shatter: synthesizing biology and engineering for mechanised harvesting of sesame

Seed shattering remains a major barrier to mechanised harvesting of sesame (Sesamum indicum L.). It reduces yield potential, with reported losses that can exceed 50%, and hinders farmers’ adoption of modern harvesting technologies. This review bridges biological and engineering disciplines by providing an integrative analysis of the genetic and morphological factors in seed retention, alongside the agronomic and mechanical strategies required for efficient harvesting. Key capsule traits, such as dehiscence angle, membrane development, and seed-placental adhesion, are examined for their roles in seed retention and suitability for mechanised harvesting. Quantitative methods for assessing shattering intensity, including the TI/KE/TO index (a score for upright retention, inverted retention, and tip opening) and Langham’s capsule breakage protocol, are discussed. The review further explores advances in breeding, including the utilisation of landraces and exotic germplasm, marker-assisted selection, and identification of candidate genes and QTLs linked to shattering resistance. Mechanised harvesting methods, particularly the choice between direct and two-stage approaches, are evaluated under varying environmental conditions, with an emphasis on seed quality preservation and economic efficiency. Finally, this review is the first to propose a comprehensive ideotype framework that resolves the fundamental trade-off between field-level seed retention and mechanical threshability by systematically integrating key biological traits with engineering parameters