Ghana’s Traditional Rice Landraces Outshine Improved Varieties in Key Minerals, Study Finds

Rice feeds more people on Earth than almost any other crop, yet in Ghana the grain on supermarket shelves tells a story of paradox. The country consumes enormous quantities of rice, but between 50 and 70 percent of it arrives in shipping containers from abroad, a dependence that weighs heavily on national food security and foreign exchange reserves. A new study published in the journal Heliyon now offers a fresh reason to reconsider what Ghanaian farmers grow at home: two traditional rice landraces, cultivated for generations in the country’s Coastal Savannah zone, consistently outperformed modern improved varieties in concentrations of essential minerals, including iron, zinc, calcium, and potassium.

The research, conducted by Francis Gbefo and Phanuel Yao Klogo at the University of Ghana, is notable for its unusually rigorous design. Rather than comparing rice varieties grown on different farms under different conditions, the team grew all four genotypes side by side in the same field at the Soil and Irrigation Research Center in Kpong, receiving identical fertilizer and water. This head-to-head setup matters enormously in nutritional studies, because soil chemistry, rainfall, and postharvest handling can each shift a grain’s mineral content dramatically. By holding the environment constant, the researchers could isolate differences attributable to the plants themselves, or at least to the combination of genetics and processing.

The four contenders represented two distinct strands of Ghanaian rice agriculture. CRI-Amankwatia and CRI-Dartey are improved aromatic varieties released by the Crops Research Institute in Fumesua, Kumasi, products of a national breeding effort aimed at competing with imported rice on quality and aroma. Ex-Baika, an aromatic landrace, and Ex-Viono, a brown rice, are traditional varieties maintained by farmers in the Coastal Savannah, widely cultivated but nutritionally under-characterized in the scientific literature. The experiment used a randomized complete block design with three field replicates per genotype, plots measuring four by three meters, and a standardized fertilization regime of 90 kilograms of nitrogen per hectare split between transplanting and panicle initiation, alongside uniform phosphorus and potassium applications.

At harvest, the grains were dried to a narrow moisture window of roughly 11.5 to 12.5 percent before milling, ensuring that every sample entered analysis under comparable conditions. Each field replicate was milled separately with a Satake rice mill, and milling recoveries ranged from 70 percent for CRI-Amankwatia down to 65 percent for Ex-Viono. Here the study made a deliberate and consequential choice: while Ex-Baika was milled to polished white rice like the improved varieties, Ex-Viono was processed as brown rice, its bran layer retained in keeping with its traditional form. That decision would prove central to interpreting the results, because rice minerals are concentrated precisely in those outer layers that polishing removes.

The laboratory work followed standardized Association of Official Analytical Chemists methods. Proximate composition, meaning moisture, crude fat, crude fiber, ash, crude protein, and carbohydrate, was determined gravimetrically and by Kjeldahl digestion, with protein calculated using the conventional nitrogen-to-protein conversion factor of 6.25. Minerals were quantified by atomic absorption spectrophotometry after acid digestion, with calibration curves showing coefficients of determination of at least 0.999. Every measurement was performed in technical triplicate on each of three biological replicates, and the data passed formal tests of normality and variance homogeneity before analysis of variance. The authors candidly note one limitation: certified reference materials and recovery studies were not available, so independent verification of the mineral measurements was not possible.

The proximate results revealed a grain dominated by carbohydrate, as expected, but with meaningful genotype-specific differences. Protein ranged from 7.41 percent in CRI-Dartey to 8.37 percent in Ex-Viono, a spread that places the Ghanaian varieties at or above levels reported for newly released rice in Ethiopia and Benin. Crude fiber varied from 0.61 to 0.78 percent, again peaking in Ex-Viono, while fat spanned 0.63 to 0.71 percent and ash, the total mineral residue after incineration at 600 degrees Celsius, climbed from 0.43 percent in CRI-Amankwatia to 0.74 percent in Ex-Viono. The researchers are careful to stress that these compositional differences describe the grain’s chemistry; the study did not measure fiber functionality, glycemic response, or any physiological effect, so no health claims can be drawn directly from the numbers.

The mineral data told the more striking story. Potassium was the most abundant element in every genotype, ranging from 112.27 milligrams per 100 grams in CRI-Dartey to 125.16 in Ex-Viono, followed by magnesium at 37.38 to 41.22 milligrams per 100 grams. Calcium and sodium were lower but still significantly different among genotypes, with Ex-Viono recording 4.51 and 13.08 milligrams per 100 grams respectively. Among the micronutrients, manganese was the lone exception to the pattern, statistically indistinguishable across all four varieties at roughly 2.3 to 2.4 milligrams per 100 grams. Iron and zinc, however, differed sharply: Ex-Viono delivered 2.77 milligrams of iron and 2.16 milligrams of zinc per 100 grams, roughly double the iron and nearly double the zinc found in the two improved varieties, with Ex-Baika occupying an intermediate position. Given that iron and zinc deficiencies affect hundreds of millions of people across sub-Saharan Africa, a staple grain that accumulates twice the micronutrient load is not a trivial finding.

Yet the authors urge caution in attributing Ex-Viono’s mineral advantage to genetics alone. Because Ex-Viono was analyzed as brown rice while the other three genotypes were polished, the mineral-rich bran and germ tissues remained in the sample, and decades of research show that elements such as iron, zinc, and magnesium are unevenly distributed within the grain, concentrated in the outer layers that milling strips away. The study therefore cannot disentangle the effect of processing from the effect of genotype, a confound the researchers acknowledge explicitly. Environmental factors, including soil pH, nutrient availability, and redox conditions in the calcic vertisol at Kpong, further complicate any purely genetic interpretation. What the data do establish is a valuable baseline: under identical field conditions and documented processing, these landraces accumulate substantially more of several essential minerals than the improved cultivars currently promoted for their agronomic and aromatic qualities.

The broader context gives the findings their urgency. Ghanaian consumers have long preferred imported rice, citing perceived superiority in appearance, cleanliness, and cooking quality, and market dominance by foreign brands reinforces that preference. National programs, from the National Rice Development Strategy to Planting for Food and Jobs, along with partners such as the Japan International Cooperation Agency and the Coalition for African Rice Development, have pushed to expand domestic production and improve grain quality. Demont and Ndour, whose work on African rice value chains the authors cite, have argued that upgrading the quality of domestic genotypes is essential for market competitiveness. Nutritional characterization of the kind performed here supplies a missing piece of that puzzle, identifying genetic resources that breeders could draw upon to combine high yield and consumer appeal with superior mineral density.

The study’s authors frame their landraces as candidates for future breeding programs, and the genetic literature supports that optimism: genome-wide association studies have identified loci governing mineral accumulation in rice grain, and comparative work across Asia and Africa has repeatedly documented meaningful diversity between landraces and hybrid varieties. The researchers themselves flag the next steps. Their results come from a single site and one season’s conditions, so multi-location trials with greater replication are needed to account for genotype-by-environment interactions before breeding decisions are made. They also recommend integrating nutritional quality with agronomic traits such as yield, disease resistance, adaptability, and consumer preference, since a nutritionally superior variety that farmers will not grow or consumers will not buy helps no one. For now, the message is clear and quietly provocative: the old varieties Ghana’s farmers never abandoned may hold exactly the nutritional assets the country’s rice sector needs to compete, provided science and market strategy can bring them together.

Subject of Research: Comparative nutritional and mineral profiling of rice landraces and improved genotypes grown in Ghana

Article Title: Comparative nutritional profiling of selected rice landraces and improved genotypes grown in Ghana

Article References: Gbefo, F., & Klogo, P. Y. (2026). Comparative nutritional profiling of selected rice landraces and improved genotypes grown in Ghana. Heliyon, 12(15), Article e45552. https://doi.org/10.1016/j.heliyon.2026.e45552

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Keywords: rice, landraces, Ghana, mineral composition, iron, zinc, proximate analysis, food security, crop breeding, nutrition, agriculture, Heliyon