Introduction
Sesame (Sesamum indicum L.) is one of the world’s oldest oilseed crops, valued for its high-quality seed, grown particularly in tropical and subtropical regions. Belonging to the family Pedaliaceae, the genus Sesamum comprises 36 species, both cultivated and wild, distributed across Africa, Australia, India, Indonesia, Malaysia, and the Philippines (Bedigian Reference Bedigian2015; Pradheep et al. Reference Pradheep, Suma, Parimalan, Yadav, Swathy and Reshma2021). These species exhibit remarkable genome plasticity, with chromosomal variations ranging from diploid (2n = 26) to polyploids (tetraploid 2n = 32; octaploid 2n = 64), and genome sizes spanning 933 to 1,651 Mb (Yadav et al. Reference Yadav, Kalia, Rangan, Pradheep, Rao, Kaur, Pandey, Rai, Vasimalla, Langyan and Sharma2022). Sesame is predominantly self-pollinated, characterized by campanulate pink to purple corolla, oblong anther thecae, and dehiscent capsules that produce numerous compressed seeds with varying testa textures.
Wild Sesamum species, weedy in nature, occupy diverse ecological niches, offering a competitive advantage to thrive under harsh environments, marginal lands, roadsides, although hillsides are considered hotspots. Their ability to grow in disturbed and human-altered environments suggests that the genus has remained evolutionarily conserved over time. Notably, S. mulayanum and S. malabaricum, considered progenitors of today’s cultivated sesame, display distinct morphological features from the cultivated type, including leaf texture, capsule wall thickness, and corolla pigmentation. (Pradheep et al. (Reference Pradheep, Suma, Parimalan, Yadav, Swathy and Reshma2021). These two taxa were previously treated as a single species by Bedigian (Reference Bedigian2014). Other wild species, S. prostratum Retz., is critically endangered, restricted to coastal regions of South India (Andhra Pradesh and Tamil Nadu), and Sri Lanka. S. laciniatum J.G. Klein ex Willd is synonymized with S. prostratum, although differing in their growth habit and habitat preferences (Thirumalaisamy et al. Reference Thirumalaisamy, Pradheep, Parameswari, Celia, Suma, Kartar, Parimalan, Yadav and Singh2024). S. alatum Thonn. and S. radiatum Schumach. & Thonn. exhibit ecological plasticity as naturalized weeds, being capable of establishing in xeric substrates, including nearly pure sandy soils. In contrast, S. latifolium demonstrates broader edaphic tolerance, successfully colonizing both compact, clay-rich soils and lithosols associated with degraded rocky terrains.
The narrow genetic base of cultivated sesame has long been a constraint to breeding efforts aimed at improving yield, nutritional content, and tolerance to biotic and abiotic stresses (Kumari et al. Reference Kumari, Choudhary, Bhardwaj and Godara2020; Wacal et al. Reference Wacal, Musinguzi, Ewaju, Atibo, Alowo, Alipa and Basalirwa2024). In contrast, exploring wild sesame’s genetic potential could significantly boost the diversity and resilience of cultivated varieties, leading to improved performance in various environments, especially under marginal conditions (Langyan et al. Reference Langyan, Yadava, Sharma, Gupta, Bansal, Yadav, Kalia and Kumar2022; Lukurugu et al. Reference Lukurugu, Nzunda, Kidunda, Chilala, Ngamba, Minja and Kapinga2023). Interspecific hybridization faces compatibility barriers; yet, successful introgression of desirable traits has been achieved in previous studies. This is particularly significant for India, a major sesame producer, which holds a large collection of germplasm, but still, native wild species are unexplored (Pathak et al. Reference Pathak, Rai, Kumari and Bhat2014; Yadav et al. Reference Yadav, Kalia, Rangan, Pradheep, Rao, Kaur, Pandey, Rai, Vasimalla, Langyan and Sharma2022).
Recognizing this gap, this study undertakes a comprehensive characterization of wild Sesamum accessions to identify traits underpinning phenotypic variation and superior agronomic performance. Through the comparative evaluation of a diverse panel of wild and cultivated species, the research aims to identify novel sources of early maturity, more capsule production and seed yield traits that surpass cultivated species. By systematically exploring the phenotypic variability in wild Sesamum resources, this work establishes a foundation for broadening the genetic base of cultivated sesame. This work provides critical insights into the utility of wild sesame germplasm, laying a foundation for breeding resilient, high-yielding sesame cultivars and supporting long-term agricultural sustainability.
Materials and methods
Plant material and experimental design
The study included 53 accessions representing seven different wild sesame species – Sesamum malabaricum, S. mulayanum, S. radiatum, S. alatum, S. latifolium, S. prostratum and S. triphyllum – along with four S. indicum accessions and three cultivars of cultivated species (Table 1). The seed material was obtained from the National Genebank at ICAR–NBPGR (Indian Council of Agricultural Research – National Bureau of Plant Genetic Resources), New Delhi, India. The experiment was conducted at ICAR–NBPGR’s New Area Experimental Farm (Latitude: 28.650° N, Longitude: 77.150° E, Elevation: 228.16 m) during the kharif seasons of 2022 and 2023 using a randomized complete block design with two replications. The experimental site is characterized by a semi-arid climate and non-calcareous soil. Seeds were manually sown in 2 m rows, with a spacing of 10 cm between plants within each row and 45 cm between the rows. Standard agronomic practices were followed throughout the cropping period to ensure optimal plant growth and the accuracy of field observations. The weather conditions at the time of sowing were recorded as 32.3 °C/28 °C in 2022 and 34.7 °C/24.9 °C in 2023. Passport data and native distribution information for the wild accessions are provided in Table S1. A Geographic Information System (GIS) map was prepared using the QGIS software tool (https://qgis.org/).
List of sesame wild species with accessions and cultivated species used in this study
Table 1 Long description
The table provides a comprehensive list of 53 sesame accessions, including both wild and cultivated species, used in a study. It details the species, ploidy levels, and countries of origin. S. malabaricum and S. mulayanum are primarily from India and Sri Lanka, while S. radiatum is from West and Central Africa. Ploidy levels vary, with diploid, tetraploid, and octaploid forms noted. The cultivated species are from various Indian states. The data highlights the geographical diversity and genetic variation within sesame species, with a notable concentration of S. malabaricum and S. radiatum accessions.
Data collection and traits measured
Data were collected for 34 agro-morphological traits, including 18 qualitative and 16 quantitative characteristics, using the ‘Field Book’ app following standardized sesame descriptors provided by IPGRI and NBPGR (2004). The qualitative traits comprised plant growth type, plant growth habit, stem hairiness, leaf hairiness, leaf shape, leaf lobe incision, number of flowers per leaf axil, corolla hairiness, exterior and interior corolla colour, number of capsules per leaf axil, capsule arrangement, capsule hairiness, capsule shape, capsule dehiscence and seed colour. The quantitative traits included measurements such as plant height (cm), number of primary branches per plant, number of secondary branches per plant, internode length (cm), days to flowering initiation, days to 50% flowering, number of nodes to first flower, corolla length (cm), capsule length (cm), capsule width (cm), days to maturity, number of capsules per plant, number of seeds per capsule, test weight (g), seed area (mm2) and seed yield per plant (g). Distinct taxonomic features of the wild species were recorded according to the classification outlined by Pradheep et al. (Reference Pradheep, Suma, Parimalan, Yadav, Swathy and Reshma2021).
Statistical data analysis
The recorded data were analyzed to compute descriptive statistics such as mean, minimum, maximum, skewness, standard error, and coefficient of variation (CV). Analysis of Variance (ANOVA) was carried out to determine the significance of differences among accessions. The identification of key traits contributing to the maximum variability was analyzed using principal component analysis (PCA). Components with eigenvalues greater than 1 were considered as principal components. A dendrogram was generated to illustrate the relationships among accessions within and across species. Clustering of accessions was performed based on Mahalanobis’ D2 statistics using SPSS software (https://www.ibm.com/spss). Estimates of environmental variance (Ve), phenotypic variance (Vp) and genotypic variance (Vg) were computed. These were used to calculate the environmental coefficient of variation (ECV), genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), and broad-sense heritability (H2). All variance-related analyses were performed using the ‘variability’ package in RStudio (R version 4.4.2).
Results
Diversity of agro-morphological traits
Phenotypic variability in qualitative traits
Among the 34 agro-morphological traits analyzed, 29 traits exhibited significant diversity. However, five traits including plant growth type, number of flowers per leaf axil, number of capsules per leaf axil, capsule arrangement, and capsule dehiscence, did not show any variation. The distinguishing morphological features of both wild and cultivated sesame species are provided in Table S2. Collection sites of the different species are represented spatially in the GIS map (Fig. 1). Significant agro-morphological variability was observed in traits such as plant growth habit, stem pubescence, branching pattern, leaf pubescence, leaf shape, leaf lobe incision, corolla pubescence, exterior and interior corolla colour, number of locules per capsule, capsule pubescence, capsule shape, and seed colour among the Sesamum wild and cultivated species (Table S3 and S4). Plant growth habit varied across accessions, ranging from prostrate (e.g., S. prostratum) to erect (e.g., S. malabaricum) growth forms. Leaf morphology of S. prostratum was notably smaller compared to other wild and cultivated species. S. triphyllum, commonly referred to as ‘three-leaved sesame’, exhibited a distinctive trifoliate leaf structure (Fig. 2). Flower traits, including corolla shape, exterior and interior colour, flower lip morphology, and pubescence, showed considerable variation in wild species as compared to cultivated S. indicum (Fig. 3, Table S4). Seeds of wild species were larger, with thicker seed coats and exhibited reticulately rugose testa patterns, while cultivated species had smooth seed coats. Notably, seeds of S. alatum were endospermic, rhododendron type, and featured membranous wings at both ends. Generally, wild species possessed thicker capsules, which often did not dehisce completely, resulting in partial seed release, unlike S. indicum, which typically has fully dehiscent capsules (Fig. 4).
Geographic Information System (GIS) map illustrates the native distribution and collection sites of the wild Sesamum accessions evaluated in this study.
Figure 1 Long description
A map of India displays the distribution of six Sesamum species using distinct symbols. S. indicum is marked with a circle, S. radiatum with a square, S. prostratum with a pentagon, S. mulayanum with a cross, S. malabaricum with a triangle and S. alatum with a star. The map includes a scale bar indicating distances of 0, 500 and 1,000 kilometers. An arrow at the top indicates north. The species are distributed across various regions of India, with each symbol representing specific locations where the species are found.
Comparative agro-morphological diversity observed in whole-plant and leaf structures across the wild and cultivated sesame species. Scale bars: 10 cm for whole plants and 5 cm for leaves.
Figure 2 Long description
The image displays a collection of sesame species, each shown with a whole plant and a corresponding leaf. The top row features whole plants of S. mulayanum, S. malabaricum, S. prostratum, S. radiatum and S. triphyllum. The middle row shows S. alatum, S. latifolium and three varieties of S. indicum: PB Til-2, VRI-1 and GT-10. The bottom row presents leaves of the same species in the same order. Each plant and leaf is labeled with its species name and scale bars are present for size reference. The plants are shown in various growth forms and the leaves exhibit different shapes and sizes, highlighting the diversity among the species.
Phenotypic variability in corolla morphology within wild and cultivated sesame species. The white scale bar represents 10 mm.
Figure 3 Long description
The image shows ten different sesame flower species arranged in two rows. The top row includes S. mulayanum, S. malabaricum, S. prostratum, S. radiatum and S. triphyllum. The bottom row features S. alatum, S. latifolium, S. indicum PB Til-2, S. indicum VRI-1 and S. indicum GT-10. Each flower is distinct in shape and size, with a white scale bar next to each for reference.
Phenotypic diversity in capsule structure and seed coat characteristics among sesame wild and cultivated species. Scale bar represents 10 mm for the capsules.
Figure 4 Long description
The image displays sesame seeds and capsules from different species. The top row shows seeds of S. mulayanum, S. malabaricum, S. prostratum, S. radiatum and S. triphyllum, each with distinct textures and colors. The middle row features seeds of S. alatum, S. latifolium, S. indicum PB Til-2, S. indicum VR1-1 and S. indicum GT-10, highlighting variations in surface patterns. The bottom row presents capsules of the same species, illustrating differences in shape and size. Each seed and capsule is labeled with its species name and scale bars are present for size reference.
Phenotypic variability in quantitative traits
Significant variability was found in plant height averaged 138.33 cm, with a range from 77.80 cm (S. alatum-EC1076113) to 199.50 cm (S. radiatum-IC199446), seed yield per plant ranged from 1.25 g (S. latifolium-EC1076127) to 22.51 g (S. indicum-IC203999), with a mean values of 5 g and seed area averaged 4.83 mm2, with a range from 3.10 (S. triphyllum-EC1076132) to 7.15 (S. indicum-PB Til-2) mm2. The number of days to flowering initiation (DFI) averaged 57.71 days, with a range from 38 days (S. malabaricum-IC557250) to 88 days (S. mulayanum-IC617459). Days to 50% flowering (DFF) averaged 71.73 days, ranging from 49 days (S. indicum-GT-10) to 97 days (S. radiatum-IC208657). Days to maturity (DM) averaged 126.34 days, with a range from 88 days (S. malabaricum-IC621506) to 168 days (S. prostatum-IC641140). In contrast, the S. indicum cultivated species were recorded with phenological events slightly earlier than the wild species. For cultivated species, the average DFI was 44 d, while 61 d for DFF, and 115 days for DM. Several wild species exhibited higher values for traits such as the number of primary branches per plant, corolla length, capsule length and seed area compared to the S. indicum cultivated species. Capsule production per plant in wild accessions ranged from 20.20 (S. mulayanum – IC277406) to 245 (S. radiatum – IC409053) capsules, with an average of 97.87. The number of seeds per capsule ranged from 18.80 (S. alatum-EC1076113) to 72.70 (S. indicum-PB Til-2), with a mean of 33.17 seeds/capsule (Table S3). In general, yield-attributing traits – including number of capsules per plant, number of seeds per capsule, test weight and seed yield per plant – were lower in the wild accessions than cultivated species. Most of the quantitative traits studied showed a wide range of variation, indicating substantial phenotypic diversity.
In general, semi-erect (47.2%) was the most common growth habit among the accessions studied, followed by erect (35.8%) and prostrate (16%). Pubescence was commonly observed: on leaves (45.3%), stems (49.1%), corollas (69.8%) and capsules (49.1%), often with high density, particularly in wild species. Leaf lobe incision was either absent (44.3%) or strong (41.5%), indicating substantial variability in leaf structure. In wild accessions, the predominant corolla coloration was pink, occurring in 60.4% of accessions on the exterior and 69.8% on the interior. In contrast, cultivated species generally exhibited predominantly white corollas, often with a pinkish tinge. The capsule shape in cultivated S. indicum was generally narrow and oblong, but wild species exhibited high morphological diversity in capsule shape. Regarding seed coat colour, the majority of accessions had grey seeds (40.5%), followed by brown (17%), light brown (13.2%), black (13.2%), reddish-brown (11.3%) and white (3.8%) (Table S4). This lack of variation may indicate the conserved nature of these traits across different Sesamum species.
Statistical analysis
A comprehensive statistical analysis was conducted to assess the phenotypic diversity of the sesame germplasm. ANOVA revealed highly significant variation (p ≤ 0.01) for most studied traits among the 53 accessions, indicating substantial agro-morphological diversity. The study revealed significant variability in key agro-morphological traits, with high coefficient of variation (CV%) observed for seed yield per plant (19.66%), number of secondary branches (15.71%), and internode length (14.38%). Conversely, seed area showed low variation (2.00%), indicating uniformity across accessions (Table 2, Table S5). Both PCV and GCV were high for traits like seed yield, number of branches and capsule number, suggesting that these traits are largely influenced by genetic factors. Broad-sense heritability (H2) was exceptionally high (>99.4%) for several traits, including seed area, capsule width and length, and corolla length (Table 2), suggesting a highly heritable nature that can be explored for direct selection. Traits like the number of capsules per plant and seed yield showed high GAM, underscoring their responsiveness to selection. Seed yield per plant was found to be strongly and positively correlated with the number of capsules per plant (r = 0.78), corolla length (r = 0.41) and capsule width (r = 0.39) (Table S6).
Estimates of variability, heritability, and genetic advance for 16 of agro-morphological traits (quantitative) for wild and cultivated sesame accessions
Table 2 Long description
The table presents variability, heritability, and genetic advance for 16 agro-morphological traits in wild sesame accessions. Seed yield and secondary branches exhibit the highest genetic advance as a percentage of mean, at 162.33% and 150.16% respectively, indicating significant potential for genetic improvement. Most traits, including plant height, primary branches, and capsule width, have broad sense heritability values exceeding 98%, suggesting strong genetic control. The genotypic and phenotypic coefficients of variation are closely aligned, indicating minimal environmental influence on trait expression. Skewness values vary, with seed yield showing a high positive skew, suggesting a few accessions with exceptionally high yields. These findings highlight the potential for selective breeding in wild sesame to enhance desirable traits.
Notes: CV%: Coefficient of Variation, GCV: genotypic coefficient of Variation, PCV: phenotypic coefficient of variation, H2b: broad sense heritability, GA: genetic advance, GAM: genetic advance as percentage of mean, PH: Plant height (cm), PB: No. of primary branches per plant, SB: No. of secondary branches per plant, IL: Internode length (cm), DFI: Days to flowering initiation, DFF: Days to 50% flowering, NNF: No. of nodes to first flower, CoL: Corolla length (cm), CaL: Capsule length (cm), CaW: Capsule width (cm), DM: Days to maturity, NCP: No. of capsule per plant, NS: No. of seeds per capsule, TW: Test weight (g), SA: Seed area (mm2), SY: Seed yield (g).
PCA revealed that five principal components accounted 73.52% of the total variation (Table S7). Our PCA results would help breeders to focus on a smaller set of key traits that explain most of the variation present in germplasm. For example, in the study, PC1 accounted for a significant portion of the total variation and was strongly loaded with traits like capsule width, plant height and seed yield per plant. This tells breeders that these specific traits are the most influential for phenotypic variability and should be prioritized for selection. Further, hierarchical clustering grouped accessions into three distinct clusters, but surprisingly, accessions from the same geographical region didn’t always cluster together (Fig. 5). This suggests that genetic similarity is not strictly tied to geographic origin and that genetic compatibility for trait introgression may be higher among some wild species, particularly the presumed progenitors of cultivated sesame like S. mulayanum and S. malabaricum. These analyses would circumvent the natural incompatibility, allowing sesame breeders to harness the full potential of the diverse wild sesame germplasm.
Hierarchical clustering of wild sesame accessions. The dendrogram revealed three distinct clusters at a distance of 10.
Figure 5 Long description
A dendrogram using Ward linkage displays hierarchical clustering of wild sesame accessions. The accessions are labeled with identifiers and species names, such as S. mulayanum, S. alatum, S. malabaricum and S. radiatum. The dendrogram reveals three distinct clusters labeled I, II and III. Cluster I includes accessions like IC644697 and IC644901, primarily S. mulayanum. Cluster II contains accessions such as IC644113 and IC524795, including S. malabaricum. Cluster III features accessions like IC208061 and IC208679, mainly S. radiatum. The x-axis represents the rescaled distance cluster combine, ranging from 0 to 25.
Identification of superior wild sesame accessions with enhanced agronomic traits for breeding improvement
Here, a few novel wild species accessions outperformed cultivated species across key economically important traits. Notably, dwarf plant types were observed in accessions IC557261 (96.25 cm), IC248198 (96.18 cm), IC557231 (83.98 cm) and IC557250 (83.80 cm). Wild species accessions IC621506 and IC557250 demonstrated early maturity as compared to the cultivar GT-10 (Table 3). Several S. radiatum accessions, including IC409053 (239.43), IC204658 (212.35), IC208661 (211.50) and IC208662 (187.08), exhibited a significantly higher number of capsules per plant relative to the commercial cultivar PB Til-2. Similarly, for seed yield per plant, S. radiatum accessions IC208661 (18.16 g), IC409053 (15.74 g) and IC208662 (14.37 g), outperformed the widely cultivated PB Til-2. Superior performance was also recorded for the trait ‘number of seeds per capsule’ in accessions IC204497 (63.95), IC203999 (63.45), and IC500444 (60.25) (Table 3). These findings reaffirm the significance of wild germplasm in sesame improvement programmes, offering novel opportunities for trait enhancement and achieving genetic gains in sesame productivity.
Sesame wild species accessions with economically important traits, most beneficial to plant breeders
Table 3 Long description
The table details sesame wild species accessions with traits beneficial to plant breeders, focusing on economic importance. S. malabaricum and S. mulayanum are noted for their dwarf type, aiding in synchronous maturity and non-lodging. S. radiatum stands out with more than 15.33 primary and secondary branches and a yield per plant exceeding 9.49, making it ideal for high yield breeding. S. malabaricum's early maturity of less than 95 days allows for multiple plantings per year. The data suggests S. radiatum's potential for increased yield through more capsules per plant, with PB Til-2 as a recommended cultivated species. These traits are crucial for developing high-yield, resilient sesame varieties.
Discussion
Sesame (Sesamum indicum L.), a vital oilseed crop cultivated globally, breeding efforts have long been constrained by the limited phenotypic variability (Grewal et al. Reference Grewal, Sharma, Bharadwaj, Hegde, Sidhu, Singh, Jain, Rasool, Arya, Agrawal and Mondal2022; Tripathi et al. Reference Tripathi, Kumari, Gore, Mishra, Singh, Mishra, Gayacharan, Dikshit, Singh, Semwal and Mehra2022). This restricts advancements in productivity, resistance to seed shattering, and stress tolerance. Conversely, wild sesame relatives offer enhanced yield, stress resilience, and adaptability (Pathak et al. Reference Pathak, Rai, Kumari and Bhat2014; Yadav et al. Reference Yadav, Kalia, Rangan, Pradheep, Rao, Kaur, Pandey, Rai, Vasimalla, Langyan and Sharma2022). In this study, a comprehensive evaluation was conducted on a diverse collection of wild sesame accessions using 34 agro-morphological traits. The study reports rich variation within wild sesame germplasm (Mukhthambica et al. Reference Mukhthambica, Bisen and Ramya2023; Gedifew, Reference Gedifew2024). High phenotypic variability was observed for traits including seed area, capsule width, corolla length, 1000-seed weight (test weight), and number of capsules per plant. Such traits are prime candidates for effective selection to achieve genetic gain (Rana et al. Reference Rana, Sharma, Tyagi, Chahota, Gautam, Singh, Sharma and Ojha2015). Importantly, seed yield per plant exhibited strong positive associations with capsule number per plant, capsule width, corolla length and plant height, corroborating prior findings that emphasize the decisive role of capsule number in yield determination (Shruthi et al. Reference Sruthi, Kalaiyarasi, Sasikala and Sudha2022). Our finding related to principal components were consistent with recent research suggesting these traits should be prioritized when selecting parental breeding lines (Mukhthambica et al. Reference Mukhthambica, Bisen and Ramya2023; Sasipriya et al. Reference Sasipriya, Parimala, Balram and Eswari2023). Several wild accessions performed exceptionally well for traits such as early maturity and high capsule number (Table 3). We also observed variable seed coats in wild accessions, varying by colour for market appeal and oil content, with wild rough coats domesticated to smooth in cultivars, yet retaining wild traits like indeterminate growth, delayed maturity, and shattering that impair yield and mechanization (Paroha et al. Reference Paroha, Bhargav, Tripathi, Garg, Kawreti and Ranganatha2014). Seed shattering causes up to 50% yield loss, limiting mechanization. Wild sesame species contribute valuable alleles for shattering resistance, it would be a good idea to carry a cross between the susceptible variety TMV3 and resistant S. prostratum, where hybrids are expected to show thicker carpel membranes and delayed capsule splitting.
A recent study focused on a limited accessions of three wild species using few agro-morphological traits and biochemical analyses (Gayathri et al. Reference Gayathri, Lovely, Arya, Jayapal and Gopinath2025). Another in-situ assessment taken 13 agro-morphological traits for 27 wild relatives of sesame (Baraki et al. Reference Baraki, Gebregergis, Belay, Berhe, Fisseha and Teame2024). While previous studies concluded that wild relatives are simply a source of variation, our study covers a comprehensive integration of broad germplasm, detailed phenotyping, high-heritability analysis, and specifically quantifies the superior performance of diverse wild accessions over commercial cultivars for high-priority agronomic traits. Taxonomically rare novel features, such as the winged, endospermic seeds observed in S. alatum and the trifoliate leaf structure of S. triphyllum, were documented, demonstrating the extreme phenotypic variability not usually captured in previous assessments. Early maturity in S. malabaricum (IC21506) is a critical trait to escape climatic stress conditions and supports farming practices like intercropping or planting multiple times per year. S. radiatum accessions exhibited a significantly higher number of capsules per plant (e.g., IC409053 recorded 239.43 capsules) relative to the commercial cultivar. Such findings directly contradict previous studies, which have shown that yield-attributing traits are typically lower in wild accessions than in cultivated species. It provides a practical road map for breeders that is not offered by molecular studies, regionally limited in-situ, or biochemical studies.
Integrating desirable traits from wild Sesamum species into cultivated S. indicum is often labour-intensive and time-consuming. The primary difficulty lies in genetic compatibility barriers between wild and cultivated species. Furthermore, specific biotechnology techniques like somatic hybridization found it difficult to produce viable hybrids. However, these hurdles can be overcome using targeted techniques: interspecific hybrids have been successfully produced using ovule culture and embryo rescue methods in crosses involving S. indicum with wild species such as S. radiatum and S. alatum. Furthermore, the utilization of progenitor species like S. malabaricum and S. mulayanum can be leveraged to circumvent genetic incompatibilities. For accelerating genetic gains, modern genomic tools like marker-assisted selection (MAS) and genetic transformation increase selection effectiveness and precision. The systematic integration of conventional breeding with biotechnological methods remains the most effective strategy to access the rich wild sesame genetic reservoir for enhanced yield and stress resilience.
The identified phenotypic diversity of sesame wild accessions, offers a valuable resource base for breeding programmes focused on enhancing yield, stress tolerance and adaptability. Integrating these diverse resources with modern breeding methodologies promises productive agriculture, thereby contributing significantly to global food security and agricultural sustainability.
Conclusions
This study reveals significant agro-morphological diversity among wild species as potential genetic resources for sesame improvement. The variability in key traits, including early maturity (S. malabaricum accessions IC621506 and IC557250; S. mulayanum accessions IC557231 and IC248198), seed yield per plant (S. radiatum accessions IC208661, IC208662 and IC409053), and number of capsules per plant (S. radiatum accessions IC409053, IC204658, IC208661 and IC208662) suggests a novel and broad genetic base that can be harnessed to address several challenges in sesame breeding. The identification of promising wild accessions provides a strong foundation for targeted breeding strategies, including pre-breeding and trait introgression into cultivated varieties. The use of progenitor species such as S. malabaricum and S. mulayanum can be used to overcome genetic incompatibilities for trait introgression in cultivated species. Overall, the findings of this study support the strategic utilization of wild germplasm in sesame breeding programmes for sustainable agriculture.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S1479262125100476.
Acknowledgements
Director, ICAR-NBPGR is duly acknowledged for providing facilities to conduct the study. The authors would like to thank the former Director, ICAR-NBPGR Dr. Kuldeep Singh for his valuable support and project administration.
Author contributions
Writing original draft preparation, software, validation, formal analysis, review and editing – D.K.A. and H.V.; data acquisition – S.A., K.K., K.S., H.K. and N.M.; formal analysis – G.S.; review and editing – K.P., K.K., R.P., A.M., R.B. and M.R.; seed material – M.S. and B.S.; funding acquisition – S.K.; project administration – G.P.S.; conceptualization, methodology, visualization, review and editing, supervision, funding acquisition, project administration – R.Y.
