Tef Plants Research Articles

Transcriptomic Profile of Tef (Eragrostis tef) in Response to Drought.

The threat to world food security posed by drought is ever increasing. Tef [Eragrostis tef (Zucc.) Trotter] is an allotetraploid cereal crop that is a staple food for a large population in the Horn of Africa. While the grain of tef provides quality food for humans, its straw is the most palatable and nutritious feed for livestock. In addition, the tef plant is resilient to several biotic and abiotic stresses, especially to drought, making it an ideal candidate to study the molecular mechanisms conferring these properties. The transcriptome expression of tef leaf collected from plants grown under drought conditions was profiled using RNA-Seq and key genes were verified using RT-qPCR. This study revealed that tef exhibits a complex molecular network involving membrane receptors and transcription factors that regulate drought responses. We identified target genes related to hormones like ABA, auxin, and brassinosteroids and genes involved in antioxidant activity. The findings were compared to physiological measurements such as changes in stomatal conductance and contents of proline, chlorophyll and carotenoid. The insights gained from this work could play vital role in enhancing drought tolerance in other economically important cereals such as maize and rice.

Yield, lodging, and water use efficiency of Tef [Eragrostis tef (zucc) Trotter] in response to carbonized rice husk application under variable moisture condition.

Terminal drought and lodging are among the major yield-limiting factors for tef cultivation in the highly weathered soils of the Ethiopian highlands. Therefore, a study was conducted to assess the yield and lodging responses of tef to varying moisture depletion levels (MDL) and the application of carbonized rice husk (CRH). A two-year 4×4 factorial experiment with 20, 35, 55, and 75% MDL and 0, 291, 582, and 873 kg ha-1 of CRH was laid out in a split-plot design, with each treatment replicated four times. The pooled mean ANOVA showed leaf area index (LAI) and lodging index (LI) were not significantly influenced by the main and interaction effects of MDL and CRH (p > 0.05); however, individual year ANOVA showed that both LI and LAI were influenced by the interaction of MDL and CRH (p<0.05) in 2021 and 2022, respectively. The lowest LI (19.7%) was obtained from the application of 873 kg CRH ha-1, followed by 20.6% from 582 kg CRH ha-1 in 2022. A 20.7% LI reduction was recorded in 2022 compared to 2021. Tef plant height and number of tillers per plant were significantly affected by MDL at p<0.05 and p<0.01, respectively, but not by CRH and its interaction with MDL. The effect of MDL was significant on tef HI (p<0.01) but not on traits including grain yield, straw yield, and water use efficiency. In conclusion, the pooled mean analysis result showed that, though there was no significant difference in yield, tef irrigated at 55% MDL provided a maximum HI of 33.8%, which was 6.21% more than the control, and increased the level of lodging resistance with a LI of 31.9%, which was next to 75% MDL with 582 kg ha-1 CRH. The authors suggested that the research should further be verified across locations for wide application.

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.

First Report of the Smut Pathogen on Tef (&amp;lt;i&amp;gt;Eragrostis&amp;lt;/i&amp;gt; &amp;lt;i&amp;gt;tef&amp;lt;/i&amp;gt;) in Ethiopia

Annually both Belg and main seasons survey of tef diseases was done. In each of the 2019 and 2020 the cropping season, survey of tef diseases was done in both short rainy and long rainy seasons. The survey aimed to monitor emerging or new tef disease in major tef growing regions. During the 2019/20 and 2020/21 cropping season survey, new disease was observed in different areas. The survey aimed to collect unusual tef disease samples observed in the field and report the newly recorded disease. The samples from diseased tef varieties were collected and observed under a microscope directly without culturing because the pathogen is obligate. This disease is known to attack the reproductive organ of the tef plant before heading. The infected part of the plant was swollen and was filled with teliospores. The disease was observed on Quncho, Magna, and Boset varieties in Alaba Zone and West Arsi Zone around Negelle Arsi and Shashemene in Southern Nation Nationality and People and Oromia region, respectively. The diagnosis was easily confirmed by planting imbibed and un imbibed seeds of Quncho in a greenhouse. Imbibed seeds with teliospores of smut gave the same signs to the one observed in the field, while signs were not observed in the unimbibed seeds. The spore cells were slightly circular shapes and measure 5-10 µm in diameter was observed. On the basis of these morphological features; the disease was identified as smut. Species-level identification of this pathogen, evaluation of tef genotypes against this disease, distribution of the pathogen and host range identification is future works.

Variation Between Three Eragrostis tef Accessions in Defense Responses to Rhopalosiphum padi Aphid Infestation.

Tef (Eragrostis tef), a staple crop that originated in the Horn of Africa, has been introduced to multiple countries over the last several decades. Crop cultivation in new geographic regions raises questions regarding the molecular basis for biotic stress responses. In this study, we aimed to classify the insect abundance on tef crop in Israel, and to elucidate its chemical and physical defense mechanisms in response to insect feeding. To discover the main pests of tef in the Mediterranean climate, we conducted an insect field survey on three selected accessions named RTC-144, RTC-405, and RTC-406, and discovered that the most abundant insect order is Hemiptera. We compared the differences in Rhopalosiphum padi (Hemiptera; Aphididae) aphid performance, preference, and feeding behavior between the three accessions. While the number of aphid progeny was lower on RTC-406 than on the other two, the aphid olfactory assay indicated that the aphids tended to be repelled from the RTC-144 accession. To highlight the variation in defense responses, we investigated the physical and chemical mechanisms. As a physical barrier, the density of non-granular trichomes was evaluated, in which a higher number of trichomes on the RTC-406 than on the other accessions was observed. This was negatively correlated with aphid performance. To determine chemical responses, the volatile and central metabolite profiles were measured upon aphid attack for 4 days. The volatile analysis exposed a rich and dynamic metabolic profile, and the central metabolism profile indicated that tef plants adjust their sugars and organic and amino acid levels. Overall, we found that the tef plants possess similar defense responses as other Poaceae family species, while the non-volatile deterrent compounds are yet to be characterized. A transcriptomic time-series analysis of a selected accession RTC-144 infested with aphids revealed a massive alteration of genes related to specialized metabolism that potentially synthesize non-volatile toxic compounds. This is the first report to reveal the variation in the defense mechanisms of tef plants. These findings can facilitate the discovery of insect-resistance genes leading to enhanced yield in tef and other cereal crops.

Tef (Eragrostis tef Trotter) Responses to Nitrogen Fertigation under Semi-Arid Mediterranean Climate

Eragrostis tef (Zucc.) Trotter (tef) is a small annual grain, panicle-bearing, C4 cereal crop native to Ethiopia, where it is a major staple food. The objectives of the present study were to characterize the responses of two tef genotypes to escalating nitrogen (N) levels in terms of shoot, root, and grain biomass production, N concentration and uptake, and to determine an optimum N range at which tef performance is maximized. The N was applied in the irrigation water (Fertigation) in order to provide a consistent concentration of N in the root zone. A second goal was to test the feasibility of growing tef in the hot, arid conditions of the Northern Negev Desert. Two experiments were carried out in the Gilat Research Station (Negev region, Israel), each testing two different genotypes of tef (405B and 406W), and each including five replicates for each treatment. In the winter of 2015–2016, tef plants were grown in perlite filled pots in a walk-in plastic-covered tunnel. Five different N treatments were applied through fertigation, meaning the fertilizer was applied with the irrigation water (10, 20, 40, 80, 120 mg L−1). All other nutrients were applied at the same sufficient rate. In the summer of 2016, tef plots were sown in open-field and applied with four different rates of N fertilization (0, 30, 60, 120 mg L−1). Biomass of the different plant parts, SPAD values, N, P and K concentration, and the lodging index were recorded in each experiment. The harvest index was also calculated. Optimum N fertigation concentration in both experiments was between 40 and 80 mg L−1, under which the time to flowering was decreased, and yield and grain protein concentration were optimized. Underfertilization caused a decrease in overall plant growth, whereas overfertilization caused an increase in vegetative growth at the expense of grain yield. Potassium uptake increased along with increased N availability, whereas P uptake did not. The fertilization rate will always need to take into account local soil and climate conditions. The field experiment also pointed to low harvest index as a major limitation on tef cultivation in the Northern Negev.

Silicon Enhances Biomass and Grain Yield in an Ancient Crop Tef [Eragrostis tef (Zucc.) Trotter

Silicon (Si) is one of the beneficial plant mineral nutrients which is known to improve biotic and abiotic stress resilience and productivity in several crops. However, its beneficial role in underutilized or “orphan” crop such as tef [Eragrostis tef (Zucc.) Trotter] has never been studied before. In this study, we investigated the effect of Si application on tef plant performance. Plants were grown in soil with or without exogenous application of Na2SiO3 (0, 1.0, 2.0, 3.0, 4.0, and 5.0 mM), and biomass and grain yield, mineral content, chlorophyll content, plant height, and expression patterns of putative Si transporter genes were studied. Silicon application significantly increased grain yield (100%) at 3.0 mM Si, and aboveground biomass yield by 45% at 5.0 mM Si, while it had no effect on plant height. The observed increase in grain yield appears to be due to enhanced stress resilience and increased total chlorophyll content. Increasing the level of Si increased shoot Si and Na content while it significantly decreased the content of other minerals including K, Ca, Mg, P, S, Fe, and Mn in the shoot, which is likely due to the use of Na containing Si amendment. A slight decrease in grain Ca, P, S, and Mn was also observed with increasing Si treatment. The increase in Si content with increasing Si levels prompted us to analyze the expression of Si transporter genes. The tef genome contains seven putative Si transporters which showed high homology with influx and efflux Lsi transporters reported in various plant species including rice. The tef Lsi homologs were deferentially expressed between tissues (roots, leaves, nodes, and inflorescences) and in response to Si, suggesting that they may play a role in Si uptake and/or translocation. Taken together, these results show that Si application improves stress resilience and yield and regulates the expression of putative Si transporter genes. However, further study is needed to determine the physiological function of the putative Si transporters, and to study the effect of field application of Si on tef productivity.

A new method for the direct tracking of in vivo lignin nanocapsules in Eragrostis tef (Poaceae) tissues.

Environmental concerns have driven scientists to research new eco-friendly approaches for the preparation of nanosystems. For this purpose, novel bio-polymers have been selected. Among these, one of the most promising is lignin, which is biodegradable and biocompatible. Additionally, lignin is one of the main by-products of the paper industry and can be re-used in nanosystems building. Lignin-based nanosystems could be used in agriculture, to improve the uptake of bioactive compounds, thus avoiding soil pollution. However, the mechanism of penetration in the plant and the route of transportation within the internal plant tissues are unknown and need to be clearly elucidated. Here we present a method of lignin nanocapsules staining and tracking by fluorochrome: Fluoral Yellow 088, which is a well-suited dye for the tracking of lipids and other oil phases. Two different applications were applied: in the first one fourteen-day plants were soaked with fluorescent nanocapsules (fNCs) pure solution and in the second one, Eragrostis tef plants were laid down on blotting paper and soaked with diluted fNCs solution. Wetting the roots of Teff plantlets with the pure fNCs solution resulted in the most efficient way of nanocapsule entrance. The dyeing of lignin nanocapsules allowed us to track them in Eragrostis tef plant tissues through microscopic observations. In particular, fNCs were proven to be able to permeate roots, reaching xylem vessels where, through water pressure, they reached the leaf.

Viability Test and Developing Inoculation Protocols for Tef Leaf Rust (Uromyces Eragrostidis) Urediniospores

Tef plants are prone to be attacked by tef leaf rust (Uromyces eragrostidis) disease under Ethiopian conditions. Tef urediniospores are considered the most economically important in maintaining disease from season to season and used as inoculums source for supporting natural infection of the disease. The longevity of freshly collected urediniospores of the tef leaf rust disease that is caused by Uromyces eragrostidis collected from different late maturing tef genotypes were studied under different temperature. Inoculation of the seedling was done with three different protocols. The first inoculation was done mixing urediniospores with tween20 and distilled water. The second inoculation was done mixing urediniospores with isoparaffin oil with distilled water and the third seedling received inoculation mixing urediniospores with distilled water. The urediniospores were placed in different refrigerators adjusted at different temperature reading from 5°C to 25°C. The collected urediniospores were kept at temperatures between 5°C and 25°C at 5°C increments. Therefore, the aims of this study are to determine the longevity of tef rust urediniospores under different temperatures and develop appropriate inoculation protocol for tef rust disease. The results revealed that 5 and 10°C were relatively the most favorable for long-term preservation for tef leaf rust urediniospores and the inoculation protocol for the seedling of tef genotypes were done using urediniospores mixed with distilled water and isoparaffin oil was best according to this study at green house.

A Proteomic Approach to Investigate the Drought Response in the Orphan Crop Eragrostis tef.

The orphan crop, Eragrostis tef, was subjected to controlled drought conditions to observe the physiological parameters and proteins changing in response to dehydration stress. Physiological measurements involving electrolyte leakage, chlorophyll fluorescence and ultra-structural analysis showed tef plants tolerated water loss to 50% relative water content (RWC) before adverse effects in leaf tissues were observed. Proteomic analysis using isobaric tag for relative and absolute quantification (iTRAQ) mass spectrometry and appropriate database searching enabled the detection of 5727 proteins, of which 211 proteins, including a number of spliced variants, were found to be differentially regulated with the imposed stress conditions. Validation of the iTRAQ dataset was done with selected stress-related proteins, fructose-bisphosphate aldolase (FBA) and the protective antioxidant proteins, monodehydroascorbate reductase (MDHAR) and peroxidase (POX). Western blot analyses confirmed protein presence and showed increased protein abundance levels during water deficit while enzymatic activity for FBA, MDHAR and POX increased at selected RWC points. Gene ontology (GO)-term enrichment and analysis revealed terms involved in biotic and abiotic stress response, signaling, transport, cellular homeostasis and pentose metabolic processes, to be enriched in tef upregulated proteins, while terms linked to reactive oxygen species (ROS)-producing processes under water-deficit, such as photosynthesis and associated light harvesting reactions, manganese transport and homeostasis, the synthesis of sugars and cell wall catabolism and modification, to be enriched in tef downregulated proteins.

Intensification and semi-intensification of tef production in Ethiopia: applications of the System of Crop Intensification.

Abstract Future strategies for sustainable food security will need to get greater productivity from available land, labour, water and other resources, producing more food, as much as possible, with reduced inputs. The System of Crop Intensification (SCI) which emerged from an agroecological production strategy developed for rice in Madagascar in the 1980s has shown promise in various countries for raising the yields of diverse crops with less reliance on purchased external inputs, using less seed and needing less water because of enhanced root growth and soil improvement. Here we review the adaptation and application of SCI principles to increasing the production and availability of Ethiopia's most important indigenous grain crop, tef. National production of this staple food, which is essential for the country's food security and is also nutritionally very beneficial, has increased in recent years since the government started supporting extension of new crop management methods after the supply of and demand for tef had become quite imbalanced. Contributing to this increase are modifications of the tef cropping system: the System of Tef Intensification (STI), which is one of many SCI derivations, and a less-intensified version designated as TIRR ( Tef with I mproved seed, R educed seed rate, and R ow planting). STI, which is based on transplanting tef seedlings rather than broadcasting tef seed, requires considerably more labour than farmers' current methods, and weather conditions must be conducive. However, the greater production from STI practices can more than repay the investment of additional labour if farmers are willing and able to make such expenditure, and if the timing of rains permits. TIRR is a less labour-demanding methodology based on drilling tef seed in rows with wide spacing. It is now being promoted by the government to raise national tef production. While it does not improve yield as much as STI does, it is easier for Ethiopian farmers to adopt. Both STI and TIRR modifications capitalize more effectively on the limited resources available to smallholding households which produce tef as their main staple crop for sustenance and for sale. TIRR includes the promotion of improved varieties of tef, while STI has shown improved yield with practically all varieties. These crop management methods draw on existing potentials within tef plants and in the soil systems where these plants grow.

Gibberellin Deficiency Confers Both Lodging and Drought Tolerance in Small Cereals.

Tef [Eragrostis tef (Zucc.) Trotter] and finger millet [Eleusine coracana Gaertn] are staple cereal crops in Africa and Asia with several desirable agronomic and nutritional properties. Tef is becoming a life-style crop as it is gluten-free while finger millet has a low glycemic index which makes it an ideal food for diabetic patients. However, both tef and finger millet have extremely low grain yields mainly due to moisture scarcity and susceptibility of the plants to lodging. In this study, the effects of gibberellic acid (GA) inhibitors particularly paclobutrazol (PBZ) on diverse physiological and yield-related parameters were investigated and compared to GA mutants in rice (Oryza sativa L.). The application of PBZ to tef and finger millet significantly reduced the plant height and increased lodging tolerance. Remarkably, PBZ also enhanced the tolerance of both tef and finger millet to moisture deficit. Under moisture scarcity, tef plants treated with PBZ did not exhibit drought-related symptoms and their stomatal conductance was unaltered, leading to higher shoot biomass and grain yield. Semi-dwarf rice mutants altered in GA biosynthesis, were also shown to have improved tolerance to dehydration. The combination of traits (drought tolerance, lodging tolerance and increased yield) that we found in plants with altered GA pathway is of importance to breeders who would otherwise rely on extensive crossing to introgress each trait individually. The key role played by PBZ in the tolerance to both lodging and drought calls for further studies using mutants in the GA biosynthesis pathway in order to obtain candidate lines which can be incorporated into crop-breeding programs to create lodging tolerant and climate-smart crops.

English

Effective chemical hybridizing agents (CHAs) or male gametocides enhance cross pollination in plant breeding and genetic analysis of traits. The present study examined the efficacy and optimum concentration of four CHAs, namely: 2-chloroethyl phosphonic acid (Ethrel), ethyl 4'-fluorooxanilate (E4FO), 2, 4-dichlorphenoxy acetic acid (2, 4-D) and Promalin ® (1.8% GA 47 – gibberellins A 4 +A 7 and 1.8% 6-BA–benzyladenine) on pollen sterility and seeding of a tef line (DZ-01-3186). Seed-derived and individually grown tef plants were treated with foliar applications of the four CHAs (at four levels each) sprayed once at the early booting stage, and bagged to control cross pollination. Female fertility was assessed by recording seed set following controlled pollinations. Although all the CHAs caused some pollen sterility, their efficacy levels varied from 9.77 to 99.50% in treated plants compared to the control (6.68 +/- 1.04%). Pollen sterility increased with increasing CHA concentration. Near-complete pollen sterility (99.50 ± 0.50%) was achieved by the application of E4FO at rates of 1500 to 3000 ppm, and Ethrel at 5000 ppm. All the CHAs significantly reduced seed yield, with E4FO, Ethrel and Promalin ® at 5000 ppm causing the highest reduction, essentially yielding no seed. In the period following the application of the CHAs, plants treated with E4FO (1000 – 1500 ppm) exhibited stigmas that remained fertile. Hence, it is recommended that E4FO (at 1000 – 1500 ppm) can be used as a chemical emasculation agent for tef, with the least phytotoxicity and the highest female fertility. Key words: Eragrostis tef, Ethrel, ethyl4-florooxanilate, female fertility, gametocides, pollen sterility.

Allelopathic Effects of Lantana (&lt;i&gt;Lantana camara&lt;/i&gt; L.) Leaf Extracts on Germination and Early Growth of three Agricultural Crops in Ethiopia

Allelopathic potential of aqueous extracts of lantana ( Lantana camara L. ) leaf on germination and growth of three agricultural crops: Maize, Finger millet and Tef, commonly cultivated in Ethiopia were studied under laboratory condition. The aqueous extracts were assayed at 5, 10, 25, 50 and 75% and their allelopathic effects were compared with distilled water (control). All the aqueous extracts did not significantly influence germination of the agricultural crops except 75% extract which significantly reduced germination of tef. All the leaf extracts stimulated root growth of maize and finger millet plants with the effect being declined with rise of concentration. In contrast, tef plants had reduced root growth in various leaf extracts with the highest reduction occurring at higher concentrations (25, 50 and 75%). The shoots of maize plants were also stimulated by all extract concentrations; whereas shoot growth of both tef and finger millet were not significantly affected by the leaf extracts. The results generally showed that lantana leaf extracts had stimulatory effects on early growth of maize and finger millet and inhibitory effects on tef growth. Keywords : Finger millet, Maize, Root growth, Shoot growth, Tef.

PLANT-DERIVED AEROSOL-SMOKE AND SMOKE SOLUTIONS INFLUENCE AGRONOMIC PERFORMANCE OF A TRADITIONAL CEREAL CROP, TEF

SUMMARYThe positive role of plant-derived smoke on seed germination and post-germination processes is well documented. The present study examined if plant-derived smoke with various methods of application influence the agronomic performance of a traditional cereal crop, tef [Eragrostis tef (Zucc.) Trotter]. Comparisons were made in potted tef plants, which germinated from seeds treated with smoke-water (1:500 dilution), Karrikinolide1 (KAR1, 10−8 M) solutions and seeds pretreated with cool aerosol-smoke for 10 min (rinsed and unrinsed afterwards). The smoke-related treatments modified a number of physiological, morphological and agronomic features of Eragrostis tef. Compared with the control, KAR1 and aerosol-smoke treatment of the seeds significantly improved plant height. All the smoke-related treatments significantly promoted stem-thickness whereas number of tillers and grain and dry biomass responded positively to aerosol-smoke and smoke-water treatments. These findings indicate that the plant-derived smoke treatment has a great potential to improve grain and dry biomass yields of tef. Moreover, due to its positive role in improving stem-thickness, smoke treatment may assist in combating lodging problems in cereals such as rice, wheat and barley, provided they are responsive to smoke treatments.

High-Throughput Discovery of Mutations in Tef Semi-Dwarfing Genes by Next-Generation Sequencing Analysis

Tef (Eragrostis tef) is a major cereal crop in Ethiopia. Lodging is the primary constraint to increasing productivity in this allotetraploid species, accounting for losses of ∼15-45% in yield each year. As a first step toward identifying semi-dwarf varieties that might have improved lodging resistance, an ∼6× fosmid library was constructed and used to identify both homeologues of the dw3 semi-dwarfing gene of Sorghum bicolor. An EMS mutagenized population, consisting of ∼21,210 tef plants, was planted and leaf materials were collected into 23 superpools. Two dwarfing candidate genes, homeologues of dw3 of sorghum and rht1 of wheat, were sequenced directly from each superpool with 454 technology, and 120 candidate mutations were identified. Out of 10 candidates tested, six independent mutations were validated by Sanger sequencing, including two predicted detrimental mutations in both dw3 homeologues with a potential to improve lodging resistance in tef through further breeding. This study demonstrates that high-throughput sequencing can identify potentially valuable mutations in under-studied plant species like tef and has provided mutant lines that can now be combined and tested in breeding programs for improved lodging resistance.

Genetic diversity in tef (Eragrostis tef) germplasm using SSR markers

The Institute of Biodiversity Conservation (IBC) in Ethiopia curates a large number of tef accessions, but there is little information about the genetic variation among the accessions. This study assessed the genetic diversity and relationships among 326 cultivated tef accessions, 13 wild relatives, and four commercial tef varieties from the U.S. using 39 SSR markers, 26 of which were flanking QTL intervals for yield, lodging index and stem strength related traits. We estimated the allelic diversity and identified markers associated with agronomic traits in this tef germplasm collection. Forty-seven loci were sufficient to differentiate 80.8% of the tef accessions. In contrast to earlier studies, genetic similarity estimates ranged from 0.21 to 0.99, indicating a high level of genetic diversity. In the course of this investigation, it was discovered that seed admixture is a serious problem affecting the integrity of almost all released tef varieties. Association was observed between the marker CNLTs540 and seed weight/plant. The majority of the alleles detected were present in tef breeding lines and varieties suggesting that tef plant breeders have been using a broad range of germplasm in their programs. The markers documented in this study will be useful to identify and verify hybrids from crosses between promising lines that lack morphological differences, an approach that was never attempted before in the tef breeding programs.

Effect of Azospirillum isolates on the growth and nitrogen content of tef [Eragrostis tef (Zucc.) Trotter

Two dizotrophi bacteria, coded as A31 and A32, were isolated from the rhizosphere of two tef varieties DZB01B354 and DZB01-196, respectively. Different morphological, biochemical, and physiological comparisons with type cultures Azospirillum lipoferum, ATCC 29707, and Azospirillum brasiliense, ATCC 29145 showed that the isolates belong to A. lipoferum. Inoculation studies of isolates on pot-grown tef plants showed marked increases in height, grain yield, total shoot and root weight, root-shoot ratio and total grain nitrogen. An increase in grain yield up to 12% over uninoculated controls was observed. The bacterial isolate A32 was found to perform better than A31 in promoting growth and yield on both homologous and heterologous tef varieties. Of the two tef varieties, DZB01B096 responded better than DZB01B354 to inoculation. The study indicats a possible specific interaction between host cultivar and bacterial isolate that governs plant yield. SINET: Ethiopian Journal of Science Vol. 23, No. 2 (December 2000), pp. 247-262 Key words/phrases: Azospirillum lipoferum, yield increase, Eragrostis tef

Callus induction and in vitro regeneration of tef [ Eragrostis tef (Zucc.) Trotter] from leaf

Summary Tef is the foremost staple cereal grain of Ethiopia. It belongs to the family Poaceae, subfamily Eragrostideae, tribe Eragrostiae and genus Eragrostis. The development and refinement of an in vitro culture system for tef is a necessary requirement for utilisation of tef in biotechnology such as genetic engineering. For a long period of time, Poaceae have been characterised as a rather recalcitrant species for in vitro culture and genetic manipulation, and only recently has progress been made with the major cereal crops. Unlike other cereals and millets, the response of tef to these emerging plant biotechnologies has not been studied; as a result this study was initiated for the first time. Immature leaf bases explan ted from 1-week-old seedlings of tef plants grown in vitro from four tef genotypes, i.e. Ada, Deschanger, Gommadie and Zuccariaginia, were plated on Murashige and Skoog media with 0, 1, 2.5, 5, 10mg/L dicamba, 2% sucrose and 0.8% agar, and incubated in the dark at a temperature of 27 °C. High frequency direct somatic embryogenesis is obtained in the dicamba concentration range of 1–5 mg/L and no direct regenerants were obtained at 10 mg/L in all of the genotypes used. Data for gradient response (embryogenic callus/direct embryo formation) of cultured leaf showed that callus induction decreased with increasing distance from the leaf base. However, in a few expiants, callus induction was obtained in the leaf tip of immature leaf. All genotypes used responded similarly. Plants from four genotypes were grown to flowering, seed setting and maturity. This first research in tef tissue culture opens a way for the use of tef in plant biotechnology, i.e. application of tissue culture and genetic engineering based technologies.