In the sun-baked fields of Ethiopia, a humble seed known as "white gold" holds the key to economic growth and nutritional security—if science can help it survive its own shortcomings.
Often seen merely as a sprinkle on hamburger buns, sesame is a crop of profound importance on the global agricultural stage. In Ethiopia, this ancient oilseed is far more than a garnish—it is the second most valuable agricultural export after coffee, earning the nation approximately $449 million in crucial foreign exchange revenue 4 . Known locally as "Selit" or "white gold," sesame supports the livelihoods of millions of smallholder farmers and plays a vital role in the national economy 4 .
Annual Export Revenue
Agricultural Export
Smallholder Farmers
Despite its economic significance, sesame is paradoxically considered an "orphan crop"—it has received scant attention from researchers, industry, and policymakers compared to other major oilseeds 4 . This neglect has left its potential largely untapped.
Average sesame yield per hectare in Ethiopia
Average sesame yield per hectare in Egypt for comparison
Sesame cultivation is a cornerstone of rural agricultural society in Ethiopia. The crop is primarily grown in the Amhara (44%), Tigray (31%), and Oromia (13%) regions, with additional production in Benishangul-Gumuz, SNNPR, and Gambela 4 .
Sesame seeds contain about 60% oil, the highest among major oilseed crops 6 .
Ethiopia is recognized as a center of origin and diversity for cultivated sesame and its wild relatives 6 . The Ethiopian Biodiversity Institute (EBI) conserves one of Africa's most extensive sesame collections—approximately 5,000 genetically diverse accessions 6 .
| Breeding Group | Percentage of Polymorphic Loci | Genetic Characteristics |
|---|---|---|
| Accessions | 82.4% | High genetic diversity |
| Improved Varieties | 31.2% | Moderate diversity |
| Landraces | 29.6% | Moderate diversity |
| Wild Types | 8.0% | Limited diversity |
Causes 30-100% yield loss globally and 15-80% in India, inducing hypoxia that disrupts physiological processes 3 .
Can lead to 50-80% yield reduction despite sesame's relatively deep taproot system 3 .
Response varies by genotype, with different salt compounds causing varying degrees of damage 3 .
Inadequate soil fertility management represents another critical constraint on sesame production. Northern Ethiopian soils show deficient levels of organic carbon, total nitrogen, available phosphorus, sulfur, and zinc 5 7 .
The traditional "blanket" fertilizer recommendations are giving way to precision approaches tailored to specific soil conditions. Research has demonstrated the effectiveness of the AquaCrop model in predicting sesame response to different nitrogen fertilizer levels 1 .
| Nutrient | Soil Content Level | Recommended Application Rate (kg/ha) |
|---|---|---|
| Nitrogen (N) | Low | 64 kg/ha |
| Medium | 41 kg/ha | |
| Phosphorus (P₂O₅) | Low | 46 kg/ha |
| Medium | 23 kg/ha | |
| Sulfur (S) | Low | 60 kg/ha |
| Medium | 30 kg/ha |
When natural genetic variation lacks desired traits, scientists can turn to induced mutation. A groundbreaking 2023 study used ethyl methane sulphonate (EMS), a chemical mutagen, to create new genetic variants in fourteen Ethiopian sesame genotypes 9 .
Researchers selected disease-free, well-formed seeds from fourteen genotypes, including landraces and improved varieties. Seeds underwent sterilization with 3% teepol detergent, 70% ethanol, and sterile distilled water 9 .
Seeds were pre-soaked in cold tap water for 24 hours, then treated with a 0.5% EMS solution in a phosphate buffer (pH=3) for 4 hours with constant shaking 9 .
The resulting M2 generation (second mutant generation) was field-tested across three major sesame-growing environments in Ethiopia—Humera, Kebabo, and Sheraro—over two rainy seasons 9 .
Researchers recorded both quantitative traits (plant height, number of branches, capsules per plant) and qualitative traits (flower color, stem pigmentation, capsule characteristics) 9 .
| Research Tool/Reagent | Primary Function | Application in Sesame Research |
|---|---|---|
| Simple Sequence Repeat (SSR) Markers | Genetic fingerprinting | Assessing genetic diversity and population structure 2 6 |
| Ethyl Methane Sulphonate (EMS) | Chemical mutagenesis | Inducing novel genetic variations for breeding 9 |
| AquaCrop Model | Simulation modeling | Predicting crop response to water and fertilizer management 1 |
| Statistical Software (R, Python) | Data analysis | Analyzing complex relationships between traits and yields 5 7 |
The path to unlocking the full potential of Ethiopian sesame requires a multidisciplinary approach that combines traditional knowledge with cutting-edge science. The genetic diversity conserved in Ethiopia's germplasm collections represents a priceless national resource for developing improved varieties.
By leveraging modern tools—from precision agriculture models and molecular markers to induced mutation breeding—researchers can address the fundamental constraints limiting sesame productivity.
"Farmers, policymakers, researchers, and other stakeholders must intervene to enhance sesame production" 4 .
By translating scientific insights into practical solutions, Ethiopia can overcome the challenges facing its sesame sector, securing both the livelihoods of millions of smallholders and a brighter future for this historically significant crop.