Debre Zeit Research Articles

Calibration and evaluation of a CROPGRO Perennial Forage Model for Brachiaria humidicola yield simulation under future climate in subhumid environments of Ethiopia

Crop simulation models can be employed to assess the impacts of climate change and aid in strategic planning and decision making regarding forage strategies. This study focused on calibrating and assessing the performance of the CROPGRO Perennial Forage Model in simulating Brachiaria humidicola yield under projected future climates for high and moderate representative concentration pathway (RCP) scenarios in the central and western subhumid regions of Ethiopia. The model was calibrated to accurately represent rainfed growth and biomass yield, using field data from the Debre Zeit and Bako Agricultural Research Centers. Climatic data, including rainfall, temperature and solar radiation, were sourced from weather stations, whereas future climate scenarios for the near future, mid-century and end-of-century periods were derived from the CORDEX Africa outputs under RCP 4.5 and RCP 8.5. The calibration process refined species parameters related to vegetative partitioning, and enhanced the d-statistic and reduced the root mean square error (RMSE) for herbage, leaf, stem and total biomass accumulation. Despite projected decreases in leaf biomass, stem biomass is projected to increase. In addition, there are projected increases in herbage and total biomass accumulation under elevated greenhouse gas concentrations and warmer temperatures. Ultimately, the projected climate under both RCPs had no significant effect on Brachiaria humidicola grass production in Ethiopia.

Characterization of genetic diversity in Eragrostis tef (zucc.) Trotter through microsatellite and morphological markers

Eragrostis tef (Zucc.) Trotter is Ethiopia's most significantly important grain crop; however, its productivity is quite low (1.7 tons per hectare) due to a variety of issues, including the poor yield potential of varieties produced thus far. To achieve future production improvements in tef, comprehensive study of the crop's genetic variability and variety, utilizing both genetic and morphological markers, necessary. The study was designed to assess the genetic diversity of 64 tef genotypes utilizing 10 Simple Sequence Repeats (SSRs) markers. This investigation took place at the Agricultural Biotechnology Research Center in Holeta, Ethiopia. Field phenotypic diversity evaluation was conducted at two distinct locations: Debre Zeit and Worabe, applied a simple lattice design during 2020/21 season. Molecular analysis of variance demonstrated a substantial proportion of variation among individuals (46 %), followed closely variation among individuals (43 %), with the least variation observed within population (11 %). Concurrently, analysis of morphological data, encompassing twenty phenotypic characteristics, revealed significant variation (P ≤ 0.01) among almost all the tested genotypes for recorded parameters, as indicated by combined analysis of variance across sites. These findings underscore the high diversity among the studied genotypes, suggesting a considerable potential for crop improvement through direct selection and intra-specific hybridization strategies. From the perspectives of both conservation and utilization of tef genetic materials, there is a pressing need for more extensive and systematic molecular level research. Promoting field trials and genotype-by-environment interaction research is crucial. These efforts will enhance our understanding of tef genetic and contribute to its effective conservation and utilization.

Character Association and Path Coefficient Analysis of Morphological Quantitative Traits in Ethiopian Kale (Brassica Carinata A.)

The present study was conducted at Debre zeit Agricultural Research Center to determine the extent of association among yield and its related traits of 49 accessions and to assess the direct and indirect effects of yield component traits on leaf yield of Ethiopian Kale. The accession were studied for fourteen quantitative traits using 7 × 7 simple lattice design in 2018 cropping season. The accessions were collected from diverse agro ecological area. The research findings indicated that leaf yield per plant exhibited positive and significant phenotypic and genotypic association with all factors except for leaf width and leaf petiole thickness. The result revealed that days to first leaf picking, leaf fresh weight per plant, leaf dry matter content and number of leaves per plant were the most important yield components as they exerted positive direct effect on leaf yield as well as positive genotypic and phenotypic association with each other explaining the existence of significant association. This highlighting their importance in improving Ethiopian kale yield.

Response of Durum Wheat to Deficit Irrigation

Deficit irrigation trial has been conducted to see the response of durum wheat to the extent of deficit irrigation at Debre Zeit research center for three successive seasons from 2016 to 2018. Establishment irrigations were given for all plots after swing and irrigation water application events were monitored using long term meteorological data and soil moisture readings. Irrigation water application depths (amount of water applied) were calculated from cumulative crop evapotranspiration (ETc) values in a given period and plots were irrigated with depths that was replenish 100 %, 75%, and 50 % of the cumulative ETc as per the treatment to be applied. Measured amount of irrigation water applied to every plot measured by using 3 inch Parshall flume. Results indicated those grain yields significantly affected by deficit irrigation levels and furrow irrigation methods. The highest mean grain yield of 5.8 t/ha attained from 75% ETc irrigation level with alternate furrow irrigation method while the lowest mean yield of 3.989 t/ha was obtained from treatment irrigated with 50% ETc and conventional furrow irrigation method. Therefore, based on the current findings, the highest grain yield was obtained at 75% ETc with alternate furrow irrigation system while the highest WUE was recorded at irrigating 100% ETc with alternate furrow system.

Morphological characterization of shallot (Allium cepa L. var. aggregatum) segregating populations obtained from natural-outcrossing in Ethiopial-outcrossing in Ethiopia

Shallot is a vegetable and condiment crop widely used in Ethiopia and globally. However, absence of improved and adaptable varieties has been the major cause of low productivity. Narrow genetic base of local shallot germplasm owing to vegetative reproduction of the crop, among others, has been the root cause of low productivity. Nevertheless, some plants within the germplasm were observed bolting and producing viable seeds, presenting an opportunity for genetic diversification. Consequently, a germplasm enhancement program was initiated using these naturally outcrossing genotypes where about eighty-one genotypes were generated. The present study was thus undertaken with the objective of characterizing, classifying, and selecting the eighty-one genotypes for future breeding activities. The genotypes were planted in 9x9 simple lattice design with two replications at Debre Zeit Agricultural Research Center (Ethiopia) during the dry (irrigated) season of 2021. The genotypes were evaluated for fifteen growth, yield, and quality traits. Significant variations were observed among the genotypes in terms of bulb yield, bulb height and diameter, total soluble solids, bolting percentage, and bulb skin color. Bulb yield of the genotypes ranged from 31.33 t/ha in DZSHT-79-1A to 9.63 t//ha in DZSHT-45-1A-1. DZSHT-51-2 (207.93 g) was the highest yielder per plant whereas DZSHT-065-6/90 (74.51 g) was the lowest yielder. DZSHT-14-2-1/90 had the thickest bulb (44.69 mm) significantly thicker than twenty two genotypes which had bulb diameter ranging from 28.92 mm to 20.29 mm. DZSHT-81-1/90 was a genotype with the longest bulb height (52.33 mm) while DZSHT-147-1C was a genotype with the shortest bulb (33.12 mm). DZSHT-307-1/90 had the highest TSS (16.78°Brix) significantly differing from DZSHT-002/07 which had the lowest TSS (11.17 °Brix). Dry matter of the genotypes ranged from 12.00% to 22.79%. DZSHT-004/07, DZSHT-111-2-1, DZSHT-41-2B and DZSHT-72-2 had DM% greater than 20% which coupled with greater than 14 °Brix could make them suitable for dehydrated shallots. Among the 81 genotypes characterized 4 (4.9%), 7 (8.6%), 13 (16.1%), 28 (34.6%) and 29 (35.8%) were yellow, golden, light red, red and dark red in colour, respectively. Fifteen of the genotypes had at least 50% bolting plants whereas twenty nine of the genotypes had less than 25% bolting. The results revealed that seven principal components explained approximately 76% of the observed variation. Cluster analysis grouped the genotypes into seven clusters, with the majority falling into three clusters. The study successfully identified genotypes with diverse and important traits and availed both the genotypes and the information for future breeding programs. These genotypes could be used for the development of improved hybrid and open pollinated shallot varieties with higher yield, quality and pest resistance/tolerance attributes.

Growth, yield and grain quality responses of Durum Wheat (Triticum turgidum var. durum) cultivars to irrigated and rain-fed production systems at Debre Zeit, central Ethiopia

Growth, yield and grain quality responses of Durum Wheat (Triticum turgidum var. durum) cultivars to irrigated and rain-fed production systems at Debre Zeit, central Ethiopia

Survey of Major Diseases on Medicinal and Aromatic Plants Growing Areas of Ethiopia

Medicinal and aromatic plants are industrial plant that are primarily used for therapeutic, aromatic and culinary purposes as components of cosmetics, medicinal products, health foods and other natural health products. Like other cereal crops, these potential medicinal and aromatic plants are constantly in grave danger from disease attack. The aim of this study was to assess the most prevalent diseases on prioritized medicinal and aromatic plants. Survey was conducted at Wondo Genet Agricultural research stations and herb growing companies in Ethiopia. Survey fields were observed from vegetative to maturity stage of the plant to assess the pest status. A total of 11 medicinal and aromatic plants were assessed in four different locations and these herbs were attacked by various diseases. Rust disease was the most serious problem on Aloe vera and Lemon grass, accounting for 30-40 percent of disease severity at Wondo Genet. In Butajira, powdery mildew was the most common disease found on sage, with a 20 percent severity. Downy mildew was recorded as a major disease on basil plants in Hawassa and Debre Zeit, with a 30-35 percent severity. Therefore, identification of the pathogen's causing agents and integrated disease management for the major recorded diseases of medicinal and aromatic plants needs further research.

Biochemical Characterization of Ethiopian Black Cumin (Nigella sativa L.).

Black cumin (Nigella sativa L.) seed oil has been used for its medicinal and aromatic values. Some studies revealed the presence of variability among N. sativa genotypes in seed oil content and yield. In Ethiopia, very few studies were conducted to investigate the variability of N. sativa genotypes by using biochemical traits. Thus, this study was conducted at Debre Zeit and Kulumsa Agricultural Research Centers' experimental sites under field conditions during the 2021 cropping season to investigate the variability of Ethiopian N. sativa genotypes based on biochemical traits. Sixty-four genotypes were used and arranged in an 8 × 8 simple lattice design with two replications. Essential oils (EOs) and fixed oils were extracted by the respective methods of hydro distillation and solvent extraction. The univariate, bivariate, and multivariate analyses of the collected data were performed. Combined analysis of variance (ANOVA) revealed significant differences among genotypes in fixed oil yield per hectare (FOY), EO content (EOC), and EO yield per hectare (EOY). EOY had a significant positive correlation with FOY and EOC. It is expected to improve all biochemical traits by 17.39%-94.62% over the improved varieties by selection of the top 5% landraces. Therefore, genotypes 90504, 219970, and 013_ATH were the top 5% best performed landraces by FOY and EOY over the improved varieties. So, through selection, it would also be possible to improve the studied biochemical traits of the genotypes. The principal component (PC) analysis (PCA) of four biochemical traits showed 85.86% of the total variance captured by the first two PCs. EOY and FOY were the main contributor traits to the variation in the first PC, whereas FOC and EOC were the main contributor traits to the variation in the second PC. The genotypes were grouped into three different clusters based on four biochemical traits with significant intercluster distance. This showed that there was sufficient diversity among the genotypes which can be exploited for the future N. sativa improvement program in Ethiopia.

Crustal resistivity structures beneath the western flank across the Central Main Ethiopian Rift: Its implications for partial melt and pathways

The Wonji Fault Belt (WFB) and the Silti Debre Zeit Fault Zone (SDFZ) are two linear belts in the Central Main Ethiopian Rift (CMER) where recent magmatic and tectonic activities have been concentrated. To examine deep resistivity patterns, magma storage, and its path beneath the Earth's crust across the CMER, the researchers used a two-dimensional (2D) inversion model of magnetotelluric data. The time series magnetotelluric data ranging from 0.003125 to 1450.0 s were collected during >24 h of installations at 21 sites, with an average station separation of 2.5 km along a profile perpendicular to the rift from the western margin of the rift (near Butajira) to AdamiTulu (near the rift axis). This work describes the use of phase tensor analysis to determine the dimensionality and geoelectrical strike direction, as well as the estimation of geoelectric strike parameters and the 2D inversion model of MT data. The results of dimensionality analysis of the majority of our MT data show a small beta value (|β|<30) at low periods (nearly below 10 s), which indicates 1D or 2D structures, while at long periods (almost above 10 s), the data show 3D structures with a large value of |β| >30. However, from the results of the dimensionality analysis of MT data, the 2D inversion model is suitable to image the resistivity of subsurface structures. The dominant geo-electrical strike is estimated to be N150E using a Z-invariant and phase tensor azimuth. The 2D inversion model was performed after the MT data were rotated to the proper geoelectric strike direction of N150E. The desired 2D inversion of the resistivity model was obtained for the MT profile using joint inversion of TE (transverse electric) and TM (transverse magnetic) mode data with an RMS misfit of 1.11. The results of the 2D inversion model reveal partial melt and upper crustal fracture zone (fault). They are attributed to a large mass of batholithic or magmatic intrusion found at a depth of 12–22 km that is characterised by a resistivity of <5 Ωm. The partial melt extends beneath stations B07 to B11 along SDFZ with a horizontal width of approximately 10 km. It could be related to the source of heat for the Ashute and Aluto geothermal fields.

Identification of Stem Rust Resistance Genes in Released Wheat Varieties by Linked SSR Markers and Phenotypic Screening

Wheat suffers significant yield losses due to stem rust disease caused by Puccinia graminis Pers. f. sp. tritici Eriks and Henn. Molecular level assessment of existing Sr genes in improved and advanced wheat materials combined with phenotypic screening lays down the basis for effective varietal development against this production constraint. Therefore, this study was carried out: to detect stem rust resistance genes present in Ethiopian bread wheat and durum wheat varieties using molecular markers; and to determine their effectiveness for the virulent Ethiopian stem rust races including Ug99. Screening of 49 wheat varieties with 11 SSR markers linked to 11 Stem rust resistance genes resulted in the detection of 5 Stem rust resistance genes (<i>Sr22, Sr25, Sr24, Sr77</i> and <i>SrTA10187</i>) in a subset of 12 varieties. The detected number of genes ranged between 1 and 2 per genotype. Despite amplifying the expected fragment, the markers have also resulted in several off-target amplifications suggesting the need to develop other relatively stable markers specific to the target genes. Field resistance screening at Debre Zeit Research Center resulted in 20 varieties showing good resistance to stem rust of which 2 are durum wheat cultivars and the rest 18 are bread wheat varieties. Recent data in 2022, however, showed only 5 out of the 20 had a resistant reaction while the other even became susceptible. For instance, most of the mega bread wheat cultivars like Ogolcho also were defeated due to the newly emerging race TTKTT. Among the genes detected by molecular markers, only <i>SrTA10187</i> seems to be effective against the rust population in the field. Seedling resistances screening gave a range of proportion of Resistant (R) to Susceptible (S) variety varying from 12:36 for TTKTT; 40:8 for TKTTF; 39:9 for TTKSK and 44:4 for TTTTF. Eight varieties (Sulla, Galil, Huluka, Kingbird, Millenium, Obsa, Tate and Ilani) exhibited resistant reaction consistently across the four pathotypes. Nine varieties (Honqollo, Millenium, Kulkulu, Shorima, Hogana, Meraro, Ilani and Galil) identified as resistant at both seedling and Adult plant stage. The genes, <i>Sr22</i> in variety Oda and <i>Sr25</i> in variety Dinknesh appeared to be effective for TTKTT, TKTTF, TTKSK and TKTTF, TTKSK, TTTTF, respectively. The detected Stem rust resistance genes in the present study which are effective against the pathotyeps combined with the resistant varieties at seedling and adult plant stage can support the wheat breeding program towards improving the crop.

Influence of seed rate and row spacing on seed multiplication factor and yield of durum wheat in Ethiopia

AbstractOptimum seeding rate and row spacing are important for uniform crop establishment and harvest of quality seed. Field experiment was conducted at three locations in 2014 and 2015 to study the influence of seed rate and row spacing on seed multiplication factor and yield of durum wheat. Triplicate split plot design was used. The highest seed yield was found at a seed rate of 125 kg ha−1 with a row spacing of 10 cm in 2014 but not significant with the seed rates of 100 kg ha−1 at 10 cm spacing, 75 kg ha−1 at 20 cm row spacing in 2014, and 150 kg ha−1 at 10 cm row spacing in 2015 at Debre Zeit. At Chefe Donsa, the highest seed yield (4.75 ton) was harvested at a seed rate of 100 kg ha−1. At Minjar, seed yield was not affected by seeding rate. Seed multiplication factor was higher at a seed rate of 50 kg ha−1 and spacing of 20 cm at Debre Zeit. At Chefe Donsa, the highest seed multiplication ratio (97.3) was observed in 2015 at a seed rate of 50 kg ha−1 with row spacing of 30 cm. Seed multiplication factor decreased with increasing seed rate at all testing locations. Sowing of 100 kg seeds per hectare with 20 cm spacing gave optimum seed yield over the testing locations. With limited seed availability of nucleus seed, 50 and 75 kg ha−1 with a spacing of 20 cm is appropriate to upsurge seed multiplication ratio.

Determination of Optimal Balanced Fertilizer Rate and Irrigation Scheduling for Onion Under Vertisol Soil Type

Onion is one of vegetable crops grown under irrigation. In order to improve crop production and productivity irrigation is the only solution for contributing towards food security, self-sufficiency and export market.. The Experiment was conducted in Debre Zeit Agricultural Research Center with determination of optimal balanced fertilizer rate and irrigation scheduling for Onion under Vertisol soil type to determine the optimum rate of balanced fertilizers and irrigation intervals and identify the interactive effect of nutrient and moisture levels on yield and yield quality of onion.The experimental treatments had three irrigation intervals, viz., 80%MAD, 100%MAD and 120%MAD and three Fertilizer rates of application, viz., 100kgha -1 NPSB, 150kgha -1 NPSB and 200kgha -1 , and a control fertilizer rate of 100kgha -1 urea. The design of the experimental plot was split plot in RCBD arrangement. The experimental study result showed that Crop Growth and Physiology Parameters, Yield Parameters and Water productivity had no significance difference under blended fertilizer rate application. But in irrigation intervals plant height, marketable yield and total bulb yield of onion was significantly affected. The highest total bulb yield of onion was recorded on the control irrigation (100% MAD) of the interval. Keywords: Blended fertilizer, Onion, Manageable Allowable Depletion (MAD), Irrigation Scheduling. DOI: 10.7176/JNSR/14-4-02 Publication date: February 28 th 2023

3D analysis of the MT data for resistivity structure beneath the Ashute geothermal site, Central Main Ethiopian Rift (CMER)

The Ashute geothermal field (around Butajira) is located near the western rift escarpment of the Central Main Ethiopian Rift (CMER), about 5–10 km west of the axial part of the Silti Debre Zeit fault zone (SDFZ). Several active volcanoes and caldera edifices are hosted in the CMER. Most of the geothermal occurrences in the region are often associated with these active volcanoes. The magnetotelluric (MT) method has become the most widely used geophysical technique for the characterization of geothermal systems. It enables the determination of the subsurface electrical resistivity distribution at depth. The high resistivity under the conductive clay products of hydrothermal alteration related to the geothermal reservoir is the main target in the geothermal system. The subsurface electrical structure of the Ashute geothermal site was analyzed using the 3D inversion model of MT data, and the results are endorsed in this work. The ModEM inversion code was used to recover the 3D model of subsurface electrical resistivity distribution. According to the 3D inversion resistivity model, the subsurface directly beneath the Ashute geothermal site can be represented by three major geoelectric horizons. On top, a relatively thin resistive layer (>100 Ωm) represents the unaltered volcanic rocks at shallow depths. This is underlain by a conductive body (< 10 Ωm), possibly associated with the presence of clay horizon (smectite and illite/chlorite zones), resulting from the alteration of volcanic rocks within the shallow subsurface. In the third bottom geoelectric layer, the subsurface electrical resistivity gradually increases to an intermediate range (10–46 Ωm). This could be related to the formation of high-temperature alteration minerals such as chlorite and epidote at depth, suggesting the presence of a heat source. As in a typical geothermal system, the rise in electrical resistivity under the conductive clay bed (products of hydrothermal alteration) may indicate the presence of a geothermal reservoir. Otherwise, no exceptional low resistivity (high conductivity) anomaly is detected at depth.

QTL mapping of seedling and field resistance to stem rust in DAKIYE/Reichenbachii durum wheat population.

Stem rust caused by the fungus Puccinia graminis f.sp. tritici Eriks. & E. Henn. (Pgt) threatens the global production of both durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husnot) and common wheat (Triticum aestivum L.). The objective of this study was to evaluate a durum wheat recombinant inbred line (RIL) population from a cross between a susceptible parent 'DAKIYE' and a resistant parent 'Reichenbachii' developed by the International Center for the Improvement of Maize and Wheat (CIMMYT) 1) for seedling response to races JRCQC and TTRTF and 2) for field response to a bulk of the current Pgt races prevalent in Ethiopia and Kenya and 3) to map loci associated with seedling and field resistances in this population. A total of 224 RILs along with their parents were evaluated at the seedling stage in the Ethiopian Institute for Agricultural Research greenhouse at Debre Zeit, Ethiopia and in the EIAR and KALRO fields in Ethiopia and Kenya, for two seasons from 2019 to 2020. The lines were genotyped using the genotyping-by-sequencing approach. A total of 843 single nucleotide polymorphism markers for 175 lines were used for quantitative trait locus (QTL) analyses. Composite interval mapping (CIM) identified three QTL on chromosomes 3B, 4B and 7B contributed by the resistant parent. The QTL on chromosome 3B was identified at all growth stages and it explained 11.8%, 6.5%, 6.4% and 15.3% of the phenotypic variation for responses to races JRCQC, TTRTF and in the field trials ETMS19 and KNMS19, respectively. The power to identify additional QTL in this population was limited by the number of high-quality markers, since several markers with segregation distortion were eliminated. A cytological study is needed to understand the presence of chromosomal rearrangements. Future evaluations of additional durum lines and RIL families identification of durable adult plant resistance sources is crucial for breeding stem rust resistance in durum wheat in the future.

Field Bindweed (Convolvulus arvensis) Control in Tef (Eragrostis tef (Zucc.) Trotter) through Various Herbicide Combinations

Field bindweed is the major weed problem for tef producers across the central highlands of Ethiopia. Herbicide application alone or coupled with once or twice hand weeding for field bindweed control is difficult due to its biological features, labor-intensive, and time-consuming. The field trial was carried out at Debre Zeit from 2020 to 2021 cropping seasons to investigate different postemergence herbicides against the grass and broadleaf weeds, in general, and field bindweed in particular, in tef farming, using a randomized complete block design with three replications. As a result, we could see that the herbicide combination had no visible effect on durum wheat’s overall performance, which makes us recommend it for the control of field bindweed. In the sequential application, a wide spectrum of herbicides (Musket Power OD 460, Pallas 45 OD, and Sekator OD 375) were applied at tillering stage, and other selective herbicides (Derby 175 SC and 2,4-diamine salt 720 g/L 720 g/L) were applied at the heading stage, and the last nonselective herbicide (Roundup) was applied at physiological maturity of tef when the Convolvulus arvensis was regrowth naturally/latecomer weed. All postemergency herbicide treatments reduced significantly both broadleaf and grass weeds, in general, and C. arvensis infestation, in particular, when compared to the weedy control. Of these, Musket Power OD 460 at tillering stage integrated with 2,4-diamine salt 720 g/L at the heading stage was more effective than other herbicides for eliminating all weeds and C. arvensis in particular throughout the crop life. This weed management option resulted in considerably enhanced weed control efficiency and weed killing potential, reduced weed dry biomass and yield loss, improved grain yield, and economic benefit with an acceptable marginal rate of return for tef growers.

EVALUATION OF RELEASED TEF (ERAGROSTIS TEF [ZUCC.] TROTTER) VARIETIES AT SOUTHWESTERN PART OF ETHIOPIA

Objective: The objective of the study was to evaluate performance and identify high yielding and stable variety for southwestern part Ethiopia and recommend identified varieties for large scale production. Experimental Materials: Eight nationally released tef varieties were included in the study. The materials were obtained from Debre Zeit Agricultural Research Center (DZARC). Design and Trial Management: The experiment was conducted during the 2019 main cropping season at six locations, namely: Melko, Gechi, Omonada, Kersa, Mana, and Gooma weredas of Southwestern Ethiopia. The trial was conducted using randomized complete block design with three replications at all locations under rain-fed conditions. Sowing was done manually. Spacing between plots was 1 m, whereas that between replications was 1.5 m and the total plot size was 2 m × 2 m. Seed rates were based on the recommendation which was 15 kg/ha. Result and Discussion: Analysis of variance revealed the presence of significant (P &lt; 0.05) differences among eight tef varieties of traits of days to heading, days to maturity, plant height, panicle length, lodging index, above ground biomass, and grain yield across locations. This indicated the presence of performance variation among the tested varieties for grain yield and it is possible to identify high yielder varieties for possible use in these locations. Conclusion and Recommendation: In general, varieties Dagim and Kora were high yielding and stable across locations and variety Gibe, Tesfa, and Negus were stable and low yielders across locations. The high yielding and stable varieties were recommendable for large scale production in southwestern part of Ethiopia. The experiment used data collected for only one season, which may limit the strength of its recommendation. However, the results are crucial in directing the breeding decision following additional season evaluation of the varieties in the same locations.

Evaluation of Adulterants in Raw Cow Milk from Selale and around Addis Ababa City, Ethiopia

Addition of milk adulterants is a serious health problem and can negatively affect the nutritional quality of milk and milk products. In this study milk samples were collected from Selale, Debre Zeit and Sebeta areas and analyzed for formalin, starch, urea, salt and water contents. Out of 180 analyzed milk samples, 42.22% were adulterated with starch, salt and water. However, formalin and urea were not detected in any of the milk samples. Percentage of adulterated milk samples collected from Selale, Debre Zeit and Sebeta were 51.66%, 48.33% and 26.66% respectively. Debre Zeit had maximum percentage of water (41.66%) and starch (6.66%) followed by Selale water (38.33%) and starch (5%). While Sebeta had the lowest percentage of contaminated milk samples with starch (3.3%) and water (21.66%). Therefore, there is a need to set control mechanisms and aware producer, milk collectors, dairy processer and consumer on impacts of adulteration. Keywords: Adulterant, Formalin, Milk, Salt, Starch, Urea, Water DOI: 10.7176/JNSR/13-9-04 Publication date: May 31 st 2022

Losses caused by stem rust (Puccinia graminis f.sp tritici) on durum wheat in Ethiopia

Stem rust caused by Puccinia graminis f.sp. tritici is one of the major biotic constraints of wheat production. The disease may cause substantial quantitative and qualitative yield losses but much of the work in Ethiopia on this pathosystem focuses on quantitative yield loss of durum wheat. This work was carried out at Debre Zeit Agriculture Research Centre during 2015/16 and 2016/17 main and off-seasons. Hence the current study was conducted with the objectives to quantify the amount of loss in grain yield due to stem rust and assess the relationship between disease parameters, grain yield, and physical quality parameters of improved durum wheat varieties grown in Ethiopia. Artificial inoculation was performed using a mixture of different dominant stem rust races. There were treated and untreated plots by fungicide that serves as protected and unprotected plots, respectively. Disease severity was recorded each 10 days interval and area under disease progress curve (AUDPC), terminal severity, and coefficient of infection were calculated. The tested cultivars exhibited different disease severity levels, having a mean value of 6.7-76%. High values of area under disease progress curve (AUDPC) were detected on Hitossa, Utuba (1225.7, 585.9). Whereas the lowest values of yield loss were recorded on CVS. Mangudo and Utuba have the mean value of yield loss of 40.2 and 44.8%, respectively. The highest yield loss was observed on susceptible variety Hitosa showing the mean value of 70%. Correlation coefficients were tested between yield losses and values of AUDPC, final stem rust severity, coefficient of infection, and rate of infection of the tested cultivars. There were strong correlation coefficients among disease parameters (r=0.72-0.99). There was also a moderately strong negative correlation coefficient among disease parameters and yield, hectoliter weight, and 1000-kernel weight of the test cultivars (r= -0.53 to -0.81). The current study indicated that the application of Rex Duo can be used in minimizing yield losses caused by the stem rust disease of durum wheat. Therefore, supporting the released durum wheat cultivars with fungicide application is the most pertinent issue in Ethiopia as most of the durum wheat cultivars in farmers' hands were moderately susceptible to susceptible cultivars Pgt races.

Boosting Chickpea Production by Optimizing Inter-Row and Intrarow Spacing at Central Highlands of Ethiopia

A field experiment was conducted to determine optimum inter-row and intrarow spacing for a higher and economic yield of different chickpea varieties during 2016–2017 cropping season at Debre Zeit and Minjar. The experiment was carried out in a split-plot design replicated three times. The two varieties (Habru and Arerti) were assigned as a main plot and factorial of three inter-row spacing (20 cm, 30 cm, and 40 cm) and three intrarow spacing (5, 10, and 15 cm) as subplot treatments. The result indicated that variety and inter-row and intrarow spacing had a significant effect on yield and yield components of chickpea at both locations. Habru variety gave higher seed and biomass yield than Arerti. The highest seed and biomass yield were recorded for the intrarow and inter-row spacing range of 5–15 × 30–40 cm, respectively. Results of the partial budget analysis showed that the highest net benefit with acceptable marginal rate of return (&gt;100%) was obtained from 10 cm × 30 cm intrarow and inter-row spacing. Therefore, 10 cm × 30 cm intrarow and inter-row spacing (330, 000 plants ha−1) can be recommended for a higher and economically optimum yield of chickpea at central highlands of Ethiopia.

Genetic characterization and genome-wide association mapping for stem rust resistance in spring bread wheat

BackgroundEmerging wheat stem rust races have become a major threat to global wheat production. Finding additional loci responsible for resistance to these races and incorporating them into currently cultivated varieties is the most economic and environmentally sound strategy to combat this problem. Thus, this study was aimed at characterizing the genetic diversity and identifying the genetic loci conferring resistance to the stem rust of wheat. To accomplish this, 245 elite lines introduced from the International Center for Agricultural Research in the Dry Areas (ICARDA) were evaluated under natural stem rust pressure in the field at the Debre Zeit Agricultural Research Center, Ethiopia. The single nucleotide polymorphisms (SNP) marker data was retrieved from a 15 K SNP wheat array. A mixed linear model was used to investigate the association between SNP markers and the best linear unbiased prediction (BLUP) values of the stem rust coefficient of infection (CI).ResultsPhenotypic analysis revealed that 46% of the lines had a coefficient of infection (CI) in a range of 0 to 19. Genome-wide average values of 0.38, 0.20, and 0.71 were recorded for Nei’s gene diversity, polymorphism information content, and major allele frequency, respectively. A total of 46 marker-trait associations (MTAs) encompassed within eleven quantitative trait loci (QTL) were detected on chromosomes 1B, 3A, 3B, 4A, 4B, and 5A for CI. Two major QTLs with –log10 (p) ≥ 4 (EWYP1B.1 and EWYP1B.2) were discovered on chromosome 1B.ConclusionsThis study identified several novel markers associated with stem rust resistance in wheat with the potential to facilitate durable rust resistance development through marker-assisted selection. It is recommended that the resistant wheat genotypes identified in this study be used in the national wheat breeding programs to improve stem rust resistance.