Jimma Agricultural Research Center

Jīma, Ethiopia

Jimma Agricultural Research Center

Jīma, Ethiopia
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Hailemichael G.,Jimma Agricultural Research Center | Catalina A.,University of Valladolid | Gonzalez M.,University of Valladolid | Martin P.,University of Valladolid
South African Journal of Enology and Viticulture | Year: 2016

The aims of this work were (i) to study the relationships between leaf water potential, foliar chlorophyll content and photosynthetic performance of grapevines under field conditions, and (ii) to evaluate the feasibility of chlorophyll fluorescence parameters to assess water status in commercial vineyards. During three consecutive seasons (2011 to 2013), 20 non-irrigated "Tempranillo" vineyard subzones were monitored in Ribera del Duero, Spain. Data on foliar chlorophyll content, midday and predawn leaf water potential, net assimilation and chlorophyll fluorescence parameters were measured at fruit set, pre-véraison and véraison. The results show that the water potential indicated weak to moderate stress in the study years and decreased along the vegetative cycle, while foliar chlorophyll contents showed an increasing trend. The correlation between both variables was not consistent. Linear regression of the chlorophyll fluorescence parameters in dark-adapted leaves, Fo, Fv and Fv/Fm, over chlorophyll content was strong in all the study years (higher determination coefficients for Fv/Fm at fruit set in 2012 and 2013). In general, the water potential with low coefficients of variation showed a low effect on photosynthesis activity, although values in variables such as Fm, Fv, Fv/Fm, Fs/Fo and ΨPSII registered an increasing trend when midday leaf water potential decreased in the pre-véraison and véraison stages. These variables could be useful to estimate water status in commercial vineyards for application in precision viticulture.


Tesfay A.,Jimma Agricultural Research Center | Kifle B.,Jimma Agricultural Research Center | Haudenshield J.S.,Urbana University | Hartman G.L.,Urbana University
Plant Disease | Year: 2017

Soybean rust (SBR), caused by Phakopsora pachyrhizi, has been reported in 10 African countries (Murithi et al. 2015) since the first report in Uganda in 1996. Soybean rust was first observed in Ethiopia in October 2011 and again in 2015 and 2016. In mid-October 2016, a severe epidemic caused “clouds,” presumably of P. pachyrhizi urediniospores, to be observed when walking through fields. In the first week of November, 11 samples (each representing at least five leaflets) were collected from JARC (7°40′N 36°50′E; elevation 1,780 m) and sent by APHIS permit to the USDA-ARS Soybean Disease and Pest Laboratory for further verification. All leaflets had uredinia (145 ± 36 μm in diameter; n = 34) and elliptical, echinulate, hyaline, pale yellowish-brown urediniospores (30.2 ± 3.5 μm length to 22.2 ± 3.2 μm width; n = 50). Uredinial density ranged from 5 to 88 (mean 42) per cm diameter based on counts from the 11 samples. In addition to uredinia, telia were observed in three of the samples. To confirm the pathogen was P. pachyrhizi, symptomatic soybean leaf tissue of less than 1 cm2 was excised from each of the 11 samples. Samples were disrupted in Lysing Matrix A and CLS-Y solution as provided by the FastDNA Spin Kit (MP Biomedicals, Solon, OH). We used two rounds of homogenization in a FastPrep FP120 lemniscate beater (MP Biomedicals) for 40 s at a speed of 6 m/s, with a 10 min incubation on ice before, between, and after. DNA was extracted as instructed by the manufacturer. The resulting eluates were diluted 10-fold with 5 mM tris, pH 8, containing 1 mM NaCl. Duplicate 5 µl subsamples were subjected to multiplex qPCR quantification of P. pachyrhizi and P. meibomiae (separately) using the primers (Frederick et al. 2002), cycling parameters, reagents, methods, and exogenous internal controls previously reported (Haudenshield and Hartman 2011) in each 25 µl reaction. Serial dilutions of previously purified SBR DNAs established linear standard curves (R2 > 0.999), with 94 to 95% amplification efficiency and enabled absolute quantification of the two species. The assay for P. pachyrhizi had a lower limit of quantification (LOQ) of 0.05 spore equivalent (SEq), and thus as little as 12.5 SEq DNA in an explant could be detected. Substantial quantities of P. pachyrhizi DNA were found in all 11 explants, ranging from 1,200 to 55,000 (mean 12,000) SEq. The assay for P. mebomiae DNA had a LOQ of 0.5 pg per assay, and thus as little as 125 pg in an explant could have been detected, but none was found. Control reactions gave the expected results, confirming the validity of the assays. Urediniospores that were dislodged from an infected leaf and inoculated in a detached-leaf assay as previously described (Twizeyimana et al. 2012) on susceptible soybean cultivar Williams 82 resulted in tan lesions after 2 weeks of incubation. This is the first confirmed report of P. pachyrhizi causing rust on soybean in Ethiopia, putting at risk 30,000 ha currently under soybean production. The reports of soybean rust in Ethiopia and adjoining countries may alter soybean production practices and research interests. Efforts to understand the virulence and genetic diversity of the pathogen in the region will be useful to develop and deploy resistant soybean cultivars. © 2017, American Phytopathological Society. All rights reserved.


Beyene A.,Jimma University | Beyene A.,Vrije Universiteit Brussel | Kassahun Y.,Jimma Agricultural Research Center | Addis T.,Jimma University | And 5 more authors.
Environmental Monitoring and Assessment | Year: 2012

Although waste from coffee processing is a valuable resource to make biogas, compost, and nutrient-rich animal food, it is usually dumped into nearby water courses. We carried out water quality assessment at 44 sampling sites along 18 rivers that receive untreated waste from 23 coffee pulping and processing plants in Jimma Zone, Ethiopia. Twenty upstream sampling sites free from coffee waste impact served as control, and 24 downstream sampling sites affected by coffee waste were selected for comparison. Physicochemical and biological results revealed a significant river water quality deterioration as a result of disposing untreated coffee waste into running water courses. During coffee-processing (wet) season, the highest organic load (1,900 mg/l), measured as biochemical oxygen demand, depleted dissolved oxygen (DO) to a level less than 0.01 mg/l, and thus curtailed nitrification. During off season, oxygen started to recuperate and augmented nitrification. The shift from significantly elevated organic load and reduced DO in the wet season to increased nitrate in the off season was found to be the determining factor for the difference in macroinvertebrate community structure as verified by ordination analysis. Macroinvertebrate diversity was significantly reduced in impacted sites during the wet season contrary to the off season. However, there was a significant difference in the ratio of sensitive to pollution-tolerant taxa in the off season, which remained depreciated in the longer term. This study highlights the urgency of research exploring on the feasibility of adopting appropriate pollution abatement technologies to implement ecologically sound coffee-processing systems in coffee-growing regions of Ethiopia. © 2011 Springer Science+Business Media B.V.


Aqueous extracts of shoot (stem + branch), leaf, flower and root of Parthenium hysterophorus L. at 0,5,10 and 15% (w/v) concentrations were applied on seeds of soybean (Glycine max L.) and haricot bean (Phaseolus vulgaris L.) to investigate their effect on percent germination, germination rate, and seedling growth (shoot and root length) and dry matter production under laboratory condition. The treatments were laid out in a completely randomized design with factorial arrangement in four replications. The trial was conducted twice, November 1 3 - 2 6 and December 1-14, 2008. Results depicted that significant (P < 0.01) difference between plant parts, concentration levels and their interaction for the aforementioned parameters. Aqueous extracts of flower at all concentrations, and leaf at 10 and 15% and shoot at 15% concentration levels 100% inhibited germination of both crops. In contrast, aqueous extracts from shoot and root at 5% had lower effect, while at higher concentrations greatly reduced germination percentage and growth of the crop. Roots of the crops were more sensitive to allelopathic effect than shoots. It is recommended that integrated weed management strategy should be designed and employed to combat the weed from soybean and haricot bean field to avoid poor germination and seedling growth and ensure sustainable production of the crops.


Gebreselassie W.,Jimma University | Mohammed A.,Jimma University | Netsere A.,Jimma Agricultural Research Center
Research Journal of Seed Science | Year: 2010

Nursery experiment was conducted to investigate the effect of removal of parchment and soaking of coffee seeds in pure water for different durations on emergence and early growth of coffee seedlings. A split plot design of three replications was employed with seed types (seeds with parchment and clean coffee) and soaking hour (soaking seeds for 12, 24, 36, 48, 60 and 72 h and control) in pure water were assigned as main and sub-plot, respectively. Emergence of seedlings was significantly (p<0.01) affected by coffee seed type (clean coffee vs. coffee with in parchment) where better emergence response was obtained from clean coffee. Forty five, 75 and 90 days after sowing 18.46, 56.70 and 84.70% emergence was obtained from clean coffee, respectively while only 1.86, 15.40 and 49.41% emergence was obtained in the same period, respectively, from coffee seeds sown in parchment. Better emergence occurred from seeds soaked in water against non-soaked ones 45 and 60 days after sowing. Moreover, leaf area and total dry matter weight differed in response to different soaking hours. The seedling vigor index also showed a statistical difference (p<0.01) between coffee seed types where clean coffee resulted in higher value (313.13) over the parchment coffee (232.48). The same parameter resulted from coffee seeds soaked for 72 h was better (p<0.05) when compared to non-soaked seeds and seeds soaked for less than 72 h The study revealed removing parchment and soaking coffee seeds in water enhances emergency and subsequent growth of coffee seedlings. © 2010 Academic Journals Inc.


Kitila O.,Jimma University | Alamerew S.,Jimma University | Kufa T.,Jimma Agricultural Research Center | Garedew W.,Jimma University
International Journal of Agricultural Research | Year: 2011

The aim of this study was to characterized and to estimate the extent of genetic variation and character association of organoleptic quality attributes of Coffea arabica accessions from Limu (Jimma, Ethiopia). Forty nine coffee germplasm accessions which have little or no information about their genetic variability together with two checks were planted in the field at Agaro Agricultural Research Sub Center, Ethiopia from 2004 to 2009. Simple lattice design with two replications was used in this particular study. Variances component method was used to estimate genetic variation, heritability and genetic advance. Relationship among traits was also estimated using standard method. The germplasm accessions differ significantly for most of the traits. Analysis of variance, variance components, phenotypic and genotypic associations, cluster analysis and principal components were computed for the sensorial quality attributes studied. The results depicted significant variations among coffee accessions for cup quality attributes studied, except aromatic intensity, bitterness, astringency and body. There was high phenotypic coefficient of variation for astringency and bitterness. This is in contrast to the low phenotypic coefficients of variation recorded for aromatic intensity and body. In principal component analysis, the first three principal components with eigen values greater than one explained 81.4% of the total variation. The first two principal components accounted with percent variability of 52.87 and 17.77%, respectively explained 70.64% of the total variability among the coffee germplasm. These were grouped into three genetically divergent clusters and three uncorrelated principal components. In general, our findings show that more than half percent of the Limu accessions had similar quality attributes with the standard checks. The results also confirmed the presence of variability in most quality attributes among the Limu coffee accessions and this could be exploited in the future genetic improvements. © 2011 Academie Journals Inc.


Kitila O.,Jimma University | Alamerew S.,Jimma University | Kufa T.,Jimma Agricultural Research Center | Garedew W.,Jimma University
International Journal of Agricultural Research | Year: 2011

To estimate the extent of genetic diversity among Limmu Coffee collection, Coffea arabica accessions from Limu (Jimma) were planted in simple lattice design with two replications. Clustering of the 49 accessions for 22 quantitative characters was performed using the method of average linkage clustering strategy of observations. Genetic divergence between clusters was determined using the generalized Mahalanobis D2 statistics Analysis of variance indicated the presence of significant (p<0.05) variability for most of quantitative traits. However, non significant variation was observed for stem diameter, canopy diameter, internode length of stem, average length of primary branch, internode length of primary branch, number of primary branch and percentage of bearing primary branches. Moreover, clustering analysis grouped the accessions in to four genetic divergent classes. The smallest inter cluster distance (D2 = 5.24) was observed between clusters I and III while the highest and highly significant inter cluster distance (D2 = 93.74) was between cluster III and cluster IV suggesting the coffee materials among clusters were divergent from each other. Furthermore, principal component analysis indicated that about 85.74% of the variation present among accessions was explained by ten principal components. Over all, the study confirmed the presence of trait diversity in Limu coffee accessions and this could be exploited in the genetic improvement of the crop through hybridization and selection. © 2011 Academic Journals Inc.


Aragaw M.,Jimma University | Alamerew S.,Jimma University | Michael G.H.,Tepi National Spices Research Center | Tesfaye A.,Jimma Agricultural Research Center
International Journal of Agricultural Research | Year: 2011

Genetic variability study generates very relevant information on the possibility of genetic improvement of crops for yield and quality attributes. The study was objectively designed to assess the genetic variability of thirty six ginger (Z. officinale Rose.) accessions. The experiment was laid out in a 6×6 simple lattice design with two replications during 2009-2010 main cropping seasons at two locations i.e., Tepi and Bahir Dar. Variances component method was used to estimate genetic variation, broad sense heritability and genetic advance. Number of plants per plot, fresh rhizome yield and dry rhizome yield showed high Genetic Coefficient of Variation (GCV) and Phenotypic Coefficient of Variation (PCV) at both locations. Relatively high heritability and genetic advance was obtained for oleoresin content, volatile oil content, fiber content, fresh rhizome yield and dry rhizome yield. The D2 analysis showed the 36 genotypes grouped into 7 and 11 clusters at Tepi and Bahir Dar, respectively. This makes the genotypes to become highly divergent. The overall assessment showed that there is wide variability among ginger accessions in Ethiopia which has an important implication for breeding ginger for yield, morphological and quality attributes. © 2011 Academic Journals Inc.


Kitila O.,Jimma University | Alamerew S.,Jimma University | Kufa T.,Jimma Agricultural Research Center | Garedew W.,Jimma University
International Journal of Agricultural Research | Year: 2011

The aim of this study was to estimate the extent of genetic variation and association among yield and yield-related traits. Forty nine Coffea arabica accessions from Limu (Jimma, Ethiopia) were tested at Agaro Agricultural Research Sub Center, Ethiopia from 2004 to 2009 in simple lattice design with two replications. Variances component method was used to estimate genetic variation, broad sense heritability and genetic advance. Association of traits was also estimated using standard method. The germplasm accessions differ significantly for most of the traits. Relatively high phenotypic (45.11 and 30.18%) and genotypic coefficient of variation (25 and 24.90%) were observed for yield and number of secondary branches in the order of magnitude. Hundred bean weight (81.13%) showed the highest heritability. Yield per plant showed significant positive phenotypic correlation with percentage of bearing primary branches (r = 0.53) while it revealed significant positive genotypic correlation with bean width (r = 0.47), fruit length (r = 0.61), hundred bean weight (r = 0.59), plant height (r = 0.28), canopy diameter (r = 0.29), leaf length (r = 0.30) and percent of bearing primary branches (r = 0.62). Over all, the study confirmed the presence of trait diversity in Limu coffee accessions and this could be exploited in the genetic improvement of the crop through hybridization and selection. © 2011 Academic Journals Inc.


Ayenew B.,Jimma Agricultural Research Center | Tefera W.,Jimma Agricultural Research Center | Kassahun B.,Jimma University
African Journal of Biotechnology | Year: 2012

Ginger (Zingiber officinale Rosc.) is the second most widely cultivated spice in Ethiopia, next to chilies. Recently, there has been huge demand for clean planting material of improved ginger cultivars, though it is difficult to meet the demand of planting materials using the conventional propagation techniques due to production inefficiency and disease transmission. Therefore, the present study was carried out with the objective of assessing the potential of axillary buds and shoot tips as explant sources and determination of suitable growth regulators for in vitro propagation of two ginger cultivars. Murashige and Skoog (MS) medium with four levels of benzyl adenine (BA) and kinetin was used for shoot multiplication in combination with two explant sources. A highly significant difference (p<0.0001) was observed between explant sources and among growth regulators for shoot multiplication. From this study, it was found that shoot tip explants on 2 mgl -1 BA and 1 mgl -1 kinetin was found to be better than other explant-media combinations which gave an average of 7 shoots per explant within six weeks of culture. Consecutively, the plantlets developed an average of 8.75 roots within four weeks of culture period and performed well in acclimatization and subsequently in the field. © 2012 Academic Journals.

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