Sesame (Sesamum indicum L.) is one of the oldest oilseed crops widely grown in Africa and Asia for its high-quality nutritional seeds. It is well adapted to harsh environments and constitutes an alternative cash crop for smallholders in developing countries. Despite its economic and nutritional importance, sesame is considered as an orphan crop because it has received very little attention from science. As a consequence, it lags behind the other major oil crops as far as genetic improvement is concerned. In recent years, the scenario has considerably changed with the decoding of the sesame nuclear genome leading to the development of various genomic resources including molecular markers, comprehensive genetic maps, high-quality transcriptome assemblies, web-based functional databases and diverse daft genome sequences. The availability of these tools in association with the discovery of candidate genes and quantitative trait locis for key agronomic traits including high oil content and quality, waterlogging and drought tolerance, disease resistance, cytoplasmic male sterility, high yield, pave the way to the development of some new strategies for sesame genetic improvement. As a result, sesame has graduated from an “orphan crop” to a “genomic resource-rich crop.” With the limited research teams working on sesame worldwide, more synergic efforts are needed to integrate these resources in sesame breeding for productivity upsurge, ensuring food security and improved livelihood in developing countries. This review retraces the evolution of sesame research by highlighting the recent advances in the “Omics” area and also critically discusses the future prospects for a further genetic improvement and a better expansion of this crop.

Abstract:Sesame is an important crop in West and Central Africa playing a role of an alternative cash crop for smallholders. However, sesame productivity is highly impaired by drought. This study aimed at identifying some drought-resistant genotypes and efficient screening traits in large sesame germplasm. Ten genotypes were examined based on 21 biochemical, physiological, agromorphological and seed quality traits under three weeks of water stress. A high variability for drought resistance was observed among the genotypes. The genotypes WC17, WC18 and WC14 were drought resistant, WC12, WC13, WC06 and WC03 were moderately drought resistant while, WC02, WC10 and WC08 were drought sensitive, based on principal component analysis. The resistant genotypes exhibited both avoidance and tolerance features including increase of the root system, reduced water loss, highest activity of antioxidative enzymes and accumulation of proline. They produced higher biomass and had higher ability to maintain seed quality under drought stress compared with the sensitive genotypes. Strong accumulation (~200% ratio stress/control) of biochemical markers including superoxide dismutase, ascorbate peroxidase, catalase and proline could be regarded as an important indicator for selecting drought resistant genotypes. This study represents a reference for future research towards developing new varieties with improved drought resistance in West and Central Africa.

Oil palm is an important crop largely produced in the world. However, its productivity is highly impaired by drought in Benin (West Africa). This study aimed at identifing the genotypic diversity in the response to drought conditions among ten oil palm genotypes (L1 to L10) in adult stage based on five predefined drought damage traits: number of green broken leaves (NGBL), number of folded leaves (NFL), number of unopened leaves (NUL) number of base leaves dry out (NBLD) and number of trees with central leaf cabbage toppled (NLCT). Principal component analysis (PCA) has shown that NGBL, NFL and NLCT are more relevant for drought study in adult palms trees. PCA has also shown a high variability in genotypes. Thus, L9, L8, L3, L1, L2 and L10 were drought tolerant whereas L7 was drought sensitive. Between these two groups, L5, L6 and L4 display intermediate tolerance to drought. Planting tolerant genotypes is a necessity to avoid drought damage. Consequently, the future research must insight the biochemical and biomolecular bases of tolerance to drought between the ten genotypes.

Objectif: La sécheresse observée en Afrique sub-saharienne est responsable de précipitations de plus en plus irrégulières d’une année à une autre qui rendent difficile la sélection et la recommandation des génotypes performants de palmier à huile. L’objectif de cette étude est d’évaluer et de classer des génotypes de palmier à huile selon leurs degrés de performance et de stabilité au fil des années. Méthodologie et résultats : Pour ce faire, des données de rendement ont été analysées chez neuf génotypes de palmier (L1 à L9) sur 18 campagnes de production (de 2000-2001 à 2018-2019) à l’aide de l’indice de supériorité génotypique (Pi) et de la régression linéaire simple. Les résultats obtenus ont montré que les génotypes L1, L2, L6 et L8 sont performants et stables et que le génotype L2 présente une adaptation spécifique aux années contraignantes. En revanche, les génotypes L3, L4, L5 et L9 sont considérés comme des génotypes peu performantes et instables. Le génotype L7 quant à lui, présente la plus faible performance. Conclusion et application des résultats : Ces résultats, en plus de fournir des détails sur les performances des 9 génotypes étudiés, ont permis d’identifier les génotypes contrastés à considérer dans les études approfondies sur l’adaptation du palmier à huile à la sécheresse. Mots clés : Palmier à huile, sécheresse, performance, stabilité, année, génotype. Yehouessi et al., J. Appl. Biosci. 2020 Analyse différentielle du rendement chez neuf génotypes de palmier à huile (Elaeis guineensis Jacq.) sous conditions de stress hydriques) 15781 Differential analysis of yield in nine genotypes of oil palm (Elaeis guineensis Jacq.) Under water stress conditions ABSTRACT Objective: The drought observed in sub-Saharan Africa is responsible for increasingly irregular rainfall from year to year, which makes it difficult to select and recommend efficient oil palm genotypes. This study aims to assess and classify oil palm genotypes according to their degrees of performance and stability over the years. Methodology and Results : Thus, yield data were analyzed in nine palm genotypes (L1 to L9) over 18 production campaigns (from 2000-2001 to 2018-2019) using the genotypic superiority index (Pi) and simple linear regression. The results obtained have shown that the L1, L2, L6 and L8 genotypes are efficient and stable and that the L2 genotype has a specific adaptation to restrictive years. In contrast, L3, L4, L5 and L9 are considered to be poorly performing and unstable genotypes. The L7 genotype has the lowest performance. Conclusion and application of results : These results, in addition to providing details on the performance of the 9 genotypes studied, made it possible to identify the contrasting genotypes to be considered in in-depth studies on the adaptation of oil palm to drought. Keywords : Oil palm, drought, performance, stability, year, genotype