Significance and prospects of an orphan crop tef

Assessment of harvest and postharvest losses of teff (Eragrostistef (Zucc.)) and methods of loss reduction: A review

Teff [Eragrostistef (Zucc.)] is one of the most important cereal crops in Ethiopia which is part of the traditional dish of the people in the form of Injera. Interest in Teff has increased noticeably due to its very attractive nutritional profile and the gluten-free nature of the grain. It is a gluten-free cereal, among the major cereal crops, Teff accounts for the largest average annual acreage in the country. It also accounts for the second-largest average annual production, next to maize. The study endeavored to review the harvest and postharvest losses, the causes of these losses, and possible solutions to reduce the postharvest losses of the Teff crop in Ethiopia. There are inadequate postharvest research works conducted in Ethiopia, and most of the limited studies are focused on cereals other than Teff. Teff farming in Ethiopia is dominated by traditional methods of harvesting and postharvest handling. The application of modernharvest and postharvest technologies during Teff production and handling is critically low. As a result, a considerable loss of Teffgrain (16-30 %) in the harvest and postharvest stages has been recorded. The largest share of this loss is observed during the harvesting stage due to shattering, scattering, animal feeding, and contamination with unwanted parts. Lack of awareness of postharvest losses, limited access and availability of postharvest technologies, and low attention given to postharvest research, extension, and infrastructure have also contributed their share to these losses. Transforming the traditional practice into mechanized farming, modern postharvest technologies, and supporting the system by further research works and pieces of training on loss prevention methods could potentially minimize the harvest and postharvest losses of Teff in the country.

Yield and lodging response of tef [Eragrostis tef (Zucc) trotter] varieties to nitrogen and silicon application rates

Lodging, poor crop varieties and nitrogen management are among the main tef cultivation problems in acidic soils of northwestern Ethiopia. Though Si has been shown to improve crop yield and lodging resistance, knowledge of its effect on tef, along genotypes and nitrogen, is yet to be uncovered. Therefore, a 4 × 2 × 2 factorial field experiment was conducted on fixed experimental plot at the Koga irrigation scheme to assess yield and lodging responses of tef varieties to nitrogen and silicon fertilizer rates during two consecutive years of 2021 and 2022. The experiment comprised four nitrogen levels: 0 (N1), 23 (N2), 46 (N3), and 92 kg N ha-1(N4), two Si levels: 0 (Si1) and 485 (Si2) kg ha-1, and two improved varieties: Hiber-1 (V1) and Quncho (V2) treatment combinations, which were replicated four times. Results showed that regardless of silicon supply and variety, nitrogen had a significant effect (p < .0001) on agronomic attributes of tef grain yield, biomass yield, harvest index, chlorophyll content, plant height, panicle length, leaf area index, and the number of plants m-2 over the two years. Application of N4, N3, and N2 improved grain yield by 166.9, 126.2, and 75.2 % over N1, respectively. The harvest index showed a declining trend with nitrogen rates, which ranged from 36.1 to 26.5 %. Hiber-1 showed a significantly (p < .01) higher panicle length than Quncho. The interaction of nitrogen, silicon, and variety significantly (p < .001) affected lodging index, with a minimum lodging index of 0 % from V1Si1N1 and a maximum lodging index (71.9 %) from V2Si1N4. Maximum net return (2552.6 USD) was obtained from V1Si1N4, while the marginal rate of return (6961.7 %) from V1Si1N3. Therefore, it can be concluded that genotype and optimum nitrogen can maximize yield and lodging resistance of tef, while silicon in the form of carbonized rice husk results no significant effect on tef lodging.

Underutilized legumes: nutrient status and advanced breeding approaches for qualitative and quantitative enhancement

Underutilized/orphan legumes provide food and nutritional security to resource-poor rural populations during periods of drought and extreme hunger, thus, saving millions of lives. The Leguminaceae, which is the third largest flowering plant family, has approximately 650 genera and 20,000 species and are distributed globally. There are various protein-rich accessible and edible legumes, such as soybean, cowpea, and others; nevertheless, their consumption rate is far higher than production, owing to ever-increasing demand. The growing global urge to switch from an animal-based protein diet to a vegetarian-based protein diet has also accelerated their demand. In this context, underutilized legumes offer significant potential for food security, nutritional requirements, and agricultural development. Many of the known legumes like Mucuna spp., Canavalia spp., Sesbania spp., Phaseolus spp., and others are reported to contain comparable amounts of protein, essential amino acids, polyunsaturated fatty acids (PUFAs), dietary fiber, essential minerals and vitamins along with other bioactive compounds. Keeping this in mind, the current review focuses on the potential of discovering underutilized legumes as a source of food, feed and pharmaceutically valuable chemicals, in order to provide baseline data for addressing malnutrition-related problems and sustaining pulse needs across the globe. There is a scarcity of information about underutilized legumes and is restricted to specific geographical zones with local or traditional significance. Around 700 genera and 20,000 species remain for domestication, improvement, and mainstreaming. Significant efforts in research, breeding, and development are required to transform existing local landraces of carefully selected, promising crops into types with broad adaptability and economic viability. Different breeding efforts and the use of biotechnological methods such as micro-propagation, molecular markers research and genetic transformation for the development of underutilized crops are offered to popularize lesser-known legume crops and help farmers diversify their agricultural systems and boost their profitability.

Grain shattering by cell death and fracture in Eragrostis tef

Abscission, known as shattering in crop species, is a highly regulated process by which plants shed parts. Although shattering has been studied extensively in cereals and a number of regulatory genes have been identified, much diversity in the process remains to be discovered. Teff (Eragrostis tef) is a crop native to Ethiopia that is potentially highly valuable worldwide for its nutritious grain and drought tolerance. Previous work has suggested that grain shattering in Eragrostis might have little in common with other cereals. In this study, we characterize the anatomy, cellular structure, and gene regulatory control of the abscission zone (AZ) in E. tef. We show that the AZ of E. tef is a narrow stalk below the caryopsis, which is common in Eragrostis species. X-ray microscopy, scanning electron microscopy, transmission electron microscopy, and immunolocalization of cell wall components showed that the AZ cells are thin walled and break open along with programmed cell death (PCD) at seed maturity, rather than separating between cells as in other studied species. Knockout of YABBY2/SHATTERING1, documented to control abscission in several cereals, had no effect on abscission or AZ structure in E. tef. RNA sequencing analysis showed that genes related to PCD and cell wall modification are enriched in the AZ at the early seed maturity stage. These data show that E. tef drops its seeds using a unique mechanism. Our results provide the groundwork for understanding grain shattering in Eragrostis and further improvement of shattering in E. tef.

Dry matter production, nitrogen yield and estimation of nitrogen fixation of legumes on vertisols of the Ethiopian highlands

Traditional land management techniques on vertisols frequently lead to soil fertility loss and land degradation. The objective of this study was to evaluate the impact of improved land preparation methods on the dry biomass and nitrogen (N) content of two legume species grown under two phosphorus fertilizer applications. The experimental design employed for these experiments was a randomized complete block design, with six treatments and four replications. Land preparation methods and phosphorus application significantly (P < 0.05) increased biomass production and N content in legumes. Over years and land preparation methods, vetch N accumulation was superior (P < 0.05) to clover and teff (Eragrostis teff). Such a large amount of N accumulation may have a positive contribution to subsequent crops when incorporated into the soil. Land preparation methods and years influenced soil mineral N accumulation, particularly under legumes. The N balance values indicated that it differed among species, land preparation methods, and P treatments over the year. The N balance of vetch +P ranged from 67.1 to 185.9 kg N ha^-1 over years and land preparation methods, whereas the comparable figure for vetch-P was 40.3-141.9 kg N ha^-1. Similarly, the N balance in clover-P ranged from 13.0 to 67.2 kg N ha^-1, and in clover +P from 13.8 to 98.6 kg N ha^-1. Teff's N balance has never exceeded 35 kg ha^-1 over the years.

Renaming Indigenous crops and addressing colonial bias in scientific language

Indigenous crops, commonly known as orphan, forgotten, or neglected crops, are understudied, but have important roles in the diet and economy of the communities that cultivate them. Here, we review potential benefits of Indigenous crop research and highlight the importance of an anticolonial framework to prevent exploitation of these unique resources.

Genome-wide transcriptome analysis of the orphan crop tef (Eragrostis tef (Zucc.) Trotter) under long-term low calcium stress

Calcium (Ca²⁺) is one of the essential mineral nutrients for plant growth and development. However, the effects of long-term Ca²⁺ deficiency in orphan crops such as Tef [(Eragrostis tef) (Zucc.) Trotter], which accumulate high levels of Ca in the grains, remained unknown. Tef is a staple crop for nearly 70 million people in East Africa, particularly in Ethiopia and Eritrea. It is one of the most nutrient-dense grains, and is also more resistant to marginal soils and climatic conditions than main cereals like corn, wheat, and rice. In this study, tef plants were grown in a hydroponic solution containing optimum (1 mM) or low (0.01 mM) Ca²⁺, and plant growth parameters and whole-genome transcriptome were analyzed. Ca⁺²-deficient plants exhibited leaf necrosis, leaf curling, and growth stunting symptoms. Ca²⁺ deficiency significantly decreased root and shoot Ca, potassium (K), and copper content in both root and shoots. At the same time, it greatly increased root iron (Fe) content, suggesting the role of Ca²⁺ in the uptake and/or translocation of these minerals. Transcriptomic analysis using RNA-seq revealed that members of Ca²⁺ channels, including the cyclic nucleotide-gated channels and glutamate receptor-like channels, Ca²⁺-transporters, Ca²⁺-binding proteins and Ca²⁺-dependent protein kinases were differentially regulated by Ca⁺² treatment. Moreover, several Fe/metal transporters, including members of vacuolar Fe transporters, yellow stripe-like, natural resistance-associated macrophage protein, and oligo-peptide transporters, were differentially regulated between shoot and root in response to Ca²⁺ treatment. Taken together, our findings suggest that Ca²⁺ deficiency affects plant growth and mineral accumulation by regulating the transcriptomes of several transporters and signaling genes.

Tef: a tiny grain with enormous potential

Tef is a highly nutritious gluten-free Ethiopian cereal with food-feed potential. However, its productivity is affected by lodging, weed infestation, terminal drought, small seed size, and shattering. Following the recent availability of tef genome sequences, we highlight the need to harness the benefits that this underutilised crop offers to improve food security.

Elucidating drought responsive networks in tef (Eragrostis tef) using phenomic and metabolomic approaches

Drought is a major abiotic stress that limits crop productivity and is driving the need to introduce new tolerant crops with better economic yield. Tef (Eragrostis tef) is a neglected (orphan) Ethiopian warm-season annual gluten-free cereal with high nutritional and health benefits. Further, tef is resilient to environmental challenges such as drought, but the adaptive mechanisms remain poorly understood. In this study, metabolic changes associated with drought response in 11 tef accessions were identified using phenomic and metabolomic approaches under controlled conditions. Computerized image analysis of droughted plants indicated reductions in leaf area and green pigments compared with controls. Metabolite profiling based on flow-infusion electrospray-high-resolution mass spectroscopy (FIE-HRMS) showed drought associated changes in flavonoid, phenylpropanoid biosynthesis, sugar metabolism, valine, leucine and isoleucine biosynthesis, and pentose phosphate pathways. Flavonoid associated metabolites and TCA intermediates were lower in the drought group, whereas most of the stress-responsive amino acids and sugars were elevated. Interestingly, after drought treatment, one accession Enatite (Ent) exhibited a significantly higher plant area than the others, and greater accumulation of flavonoids, amino acids (serine and glycine), sugars (ribose, myo-inositol), and fatty acids. The increased accumulation of these metabolites could explain the increased tolerance to drought in Ent compared with other accessions. This is the first time a non-targeted metabolomics approach has been applied in tef, and our results provide a framework for a better understanding of the tef metabolome during drought stress that will help to identify traits to improve this understudied potential crop.

Untargeted Metabolomic Profiling Reveals Variation in Metabolites Associated with Nutritional Values in Tef Accessions

Tef (Eragrostis tef), is a gluten-free orphan cereal, crop of nutritional and economical significance. Here we used untargeted metabolomics to survey metabolite variation in 14 diverse tef accessions at 15-days post germination. Tef genotypes were classified into four metabolomic groups where variation was linked to flavones and flavonols. Further analysis on white seeded accessions shows variation related to sucrose and important vitamins, nicotinamides (vitamin B3) riboflavin (vitamin B2) and folate (vitamin B9). Coloured seeded accessions showed variation in metabolism related to amino acid and sugars. This study highlights the potential of metabolomics in exploring the nutritional traits in tef.

Bambara Groundnut (Vigna subterranea L. Verdc): A Crop for the New Millennium, Its Genetic Diversity, and Improvements to Mitigate Future Food and Nutritional Challenges

The world’s food and agricultural schemes have gradually fallen into an alarming state due to challenges such as high population birth rates, diverse agro-climatic zones, a lack of measures to counter global warming, severe practices of sole-culture cultivation, and asset reduction. A very high dependency on limited staple food crops is associated with repetitious diets, deprivation of food, and shortages of trace minerals, which often causes dietary sicknesses. To ensure nutritious diets worldwide, a real-world and justifiable scheme is provided to garner extra attention towards variation in both agriculture/farming approaches and food habits. The EAT-Lancet statement emphasized an increase in agri-based diets as a way of attaining global generational health. Enlarging neglected crops with plenty of genomic stocks and potentially profitable attributes is a solution that could address food and nutritional security concerns. Bambara groundnut is one such imperative and neglected legume crop that contributes positively to improving global food and nutrient safety. As a “complete food”, this crop has recently been treated as a new millennium crop, and furthermore, it is more adjusted to poor soil and climatic conditions than other dominant crops. Bambara groundnut is a repository of vital nutrients that provides carbohydrates, crucial amino acids, proteins, and energy as well as minerals and vitamins to developed and low-income countries where animal proteins are not readily available. This review explores the potential of Bambara groundnut in ensuring food and nutrient security; its variables, production, processing, nutrient values, role in reducing the nutritional gap, and diverse uses; and attempts in improving its traits. To strengthen food production, an agricultural revolution is required for underutilized crop species to feed the ever-expanding population in the world. Henceforth, advanced plant-breeding procedures, such as next-generation breeding techniques, various molecular tools, TILLING, Eco-TILLING, proteomics, genomics, and transcriptomics (which has been used for major crops), also need to be practiced to intensify production. To boost productivity and to feed the most starved and malnourished populations of the world, it is assumed that the application of modern techniques will play a vital role in the advancement of the underutilized Bambara groundnut.

Alternative Strategies for Multi-Stress Tolerance and Yield Improvement in Millets

Millets are important cereal crops cultivated in arid and semiarid regions of the world, particularly Africa and southeast Asia. Climate change has triggered multiple abiotic stresses in plants that are the main causes of crop loss worldwide, reducing average yield for most crops by more than 50%. Although millets are tolerant to most abiotic stresses including drought and high temperatures, further improvement is needed to make them more resilient to unprecedented effects of climate change and associated environmental stresses. Incorporation of stress tolerance traits in millets will improve their productivity in marginal environments and will help in overcoming future food shortage due to climate change. Recently, approaches such as application of plant growth-promoting rhizobacteria (PGPRs) have been used to improve growth and development, as well as stress tolerance of crops. Moreover, with the advance of next-generation sequencing technology, genome editing, using the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system are increasingly used to develop stress tolerant varieties in different crops. In this paper, the innate ability of millets to tolerate abiotic stresses and alternative approaches to boost stress resistance were thoroughly reviewed. Moreover, several stress-resistant genes were identified in related monocots such as rice (Oryza sativa), wheat (Triticum aestivum), and maize (Zea mays), and other related species for which orthologs in millets could be manipulated by CRISPR/Cas9 and related genome-editing techniques to improve stress resilience and productivity. These cutting-edge alternative strategies are expected to bring this group of orphan crops at the forefront of scientific research for their potential contribution to global food security.

Orphan Crops and their Wild Relatives in the Genomic Era

More than half of the calories consumed by humans are provided by three major cereal crops (rice, maize, and wheat). Orphan crops are usually well adapted to low-input agricultural conditions, and they not only play vital roles in local areas but can also contribute to food and nutritional needs worldwide. Interestingly, many wild relatives of orphan crops are important weeds of major crops. Although orphan crops and their wild relatives have received little attentions from researchers for many years, genomic studies have recently been performed on these plants. Here, we provide an overview of genomic studies on orphan crops, with a focus on orphan cereals and their wild relatives. The genomes of at least 12 orphan cereals and/or their wild relatives have been sequenced. In addition to genomic benefits for orphan crop breeding, we discuss the potential ways for mutual utilization of genomic data from major crops, orphan crops, and their wild relatives (including weeds) and provide perspectives on genetic improvement of both orphan and major crops (including de novo domestication of orphan crops) in the coming genomic era.

Contributions of African Crops to American Culture and Beyond: The Slave Trade and Other Journeys of Resilient Peoples and Crops

There is a general unawareness of food crops indigenous to the African continent that have contributed to Western culture. This under-appreciation is particularly relevant in the current context of societal movements to end historic racism and value the contributions of peoples of African origin and African skin colors. Lack of awareness of the contributions of Africa's crops has negative practical consequences, including inadequate investments in preserving and maximizing the use of crop diversity to facilitate breeding. This paper provides an overview and analysis of African crops that have made significant contributions to the United States and globally, and/or hold potential in the twenty-first century. The paper specifically discusses watermelon, coffee, kola, rooibos, oil palm, shea, cowpea/black eyed pea, leafy greens, okra, yam, sorghum, pearl millet, finger millet, teff, and fonio. The review focuses on the intersection of these crops with racialized peoples, with a particular focus on African-Americans starting with slavery. The analysis includes the sites of domestication of African crops, their historical migration out of Africa, their sociocultural contributions to cuisines and products around the world, their uses today, and the indigenous knowledge associated with traditional cultivation and landrace selection. The untapped potential of local genetic resources and indigenous agronomic strategies are also described. The review demonstrates that African crops played an important role in the development of American cuisine, beverages and household products. Many of these crops are nutritious, high value and stress tolerant. The paper concludes that African crops hold significant promise in improving the resiliency of global food production systems, to mitigate climate change and alleviate food insecurity and rural poverty, especially in dry regions of the world. It is hoped that this review contributes to teaching the next generation of agriculturalists, food scientists and international development professionals about the valuable contributions of Africa's resilient crops and peoples.

Comparative analyses of 32 complete plastomes of Tef (Eragrostis tef ) accessions from Ethiopia: phylogenetic relationships and mutational hotspots

Eragrostis tef is an important cereal crop in Ethiopia with excellent storage properties, high–quality food, and the unique ability to thrive in extreme environmental conditions. However, the application of advanced molecular tools for breeding and conservation of these species is extremely limited. Therefore, developing chloroplast genome resources and high-resolution molecular markers are valuable to E. tef population and biogeographic studies. In the current study, we assembled and compared the complete plastomes of 32 E. tef accessions. The size of the plastomes ranged from 134,349 to 134,437 bp with similar GC content (∼38.3%). Genomes annotations revealed 112 individual genes, including 77 protein-coding, 31 tRNA, and 4 rRNA genes. Comparison of E. tef plastomes revealed a low degree of intraspecific sequence variations and no structural differentiations. Furthermore, we found 34 polymorphic sites (13 cpSSRs, 12 InDels, and 9 SNPs) that can be used as valuable DNA barcodes. Among them, the majority (88%) of the polymorphic sites were identified in the noncoding genomic regions. Nonsynonymous (ka) and synonymous (ks) substitution analysis showed that all PCGs were under purifying selection (ka/ks <1). The phylogenetic analyses of the whole plastomes and polymorphic region sequences were able to distinguish the accession from the southern population, indicating its potential to be used as a super-barcode. In conclusion, the newly generated plastomes and polymorphic markers developed here could be a useful genomic resource in molecular breeding, population genetics and the biogeographical study of E. tef.

The 21st Century Agriculture: When Rice Research Draws Attention to Climate Variability and How Weedy Rice and Underutilized Grains Come in Handy

Rice, the first crop to be fully sequenced and annotated in the mid-2000s, is an excellent model species for crop research due mainly to its relatively small genome and rich genetic diversity. The 130-million-year-old cereal came into the limelight in the 1960s when the semi-dwarfing gene sd-1, better known as the "green revolution" gene, resulted in the establishment of a high-yielding semi-dwarf variety IR8. Deemed as the miracle rice, IR8 saved millions of lives and revolutionized irrigated rice farming particularly in the tropics. The technology, however, spurred some unintended negative consequences, especially in prompting ubiquitous monoculture systems that increase agricultural vulnerability to extreme weather events and climate variability. One feasible way to incorporate resilience in modern rice varieties with narrow genetic backgrounds is by introgressing alleles from the germplasm of its weedy and wild relatives, or perhaps from the suitable underutilized species that harbor novel genes responsive to various biotic and abiotic stresses. This review reminisces the fascinating half-century journey of rice research and highlights the potential utilization of weedy rice and underutilized grains in modern breeding programs. Other possible alternatives to improve the sustainability of crop production systems in a changing climate are also discussed.