Genetic and Agromorphological Characterization of Sesame (Sesamum indicum L.) Genotypes for Dehiscence-Related Traits and Grain Yield Performances

Abstract

Sesame is of global economic, nutritional, and health importance. However, capsule dehiscence remains a major constraint in sesame production, causing significant yield losses. Thus, the objectives of this study were to (1) determine the agromorphological and genetic variability of 160 sesame genotypes based on the grain yield and traits related to capsule dehiscence and (2) identify promising parental lines for developing non semi-dehiscent genotypes. The experiment was conducted at the International Institute of Tropical Agriculture (IITA) in the Benin Republic, using an alpha-lattice 32 × 5 design with three replications. Data were collected on 25 traits, including 19 quantitative and six qualitative traits contributing to dehiscence and yield performance. The phenological and agromorphological traits, yield, and yield components of sesame cultivars were evaluated, along with genetic parameters and clusters of different groups based on their dehiscence tolerance level. Capsule dehiscence was evaluated using the sun-drying and oven-drying methods at 60°C for 6 hours. The capsule split (ECS, %) and capsule open (ECO, %) were calculated to quantify dehiscence. Descriptive and inferential statistics were performed. After classification, three clusters were identified. The first group with less resistance to shattering had shorter sizes, lower yields, fewer capsules, and smaller capsular zones. However, they had better earliness. The highly resistant individuals with a low dehiscence rate exhibited a high plant height, capsule number, and capsule length. The intermediate group with normal dehiscence rates had moderate values for all attributes. Traits such as capsule split, capsule open, number of capsules per plant, and potential yield per genotype exhibited high genetic variability. ECS and ECO recorded the highest coefficients of genotypic and phenotypic variation. The results of this study provide valuable information for the development of indehiscent and semi-dehiscent sesame genotypes with good seed retention capacity at maturity, minimizing losses due to capsule dehiscence and ultimately benefiting sesame producers and the oilseed industry.