Background Ethiopia is considered as center of diversity for barley (Hordeum vulgare L.) and it i... more Background Ethiopia is considered as center of diversity for barley (Hordeum vulgare L.) and it is grown across different agro-ecologies of the country. Unraveling population structure and gene flow status on temporal scales assists an evaluation of the consequences of physical, demographic and overall environmental changes on the stability and persistence of populations. This study was to examine spatial and temporal genetic variation within and among barley landrace samples collected over a period of four decades, using simple sequence repeat markers. Results Results from STRUCTURE, neighbor joining tree and discriminant analysis of principal component (DAPC) analysis revealed presence low-to-high genetic diversity among the landraces and grouped the landraces into three clusters. The cluster analysis revealed a close relationship between landraces along geographic proximity with genetic distance increases along with geographic distance. From analysis of molecular variance (AMOVA)...
In this study, we evaluated a collection of 585 barley landraces along with 10 checks at Sinana A... more In this study, we evaluated a collection of 585 barley landraces along with 10 checks at Sinana Agricultural Research Center (SARC) and Bale-Goba research sites in 2018/19 and 2019/20 cropping seasons for resistance to net blotch (Pyrenophora teres F. teres (Ptt)). The experiments were laid out in an augmented complete block design. Data on agronomic performance and disease response were recorded. Analysis of variance showed highly significant variations between and within the landraces and cultivars in net blotch percent severity index (PSI), area under the disease progress curve (AUDPC), apparent infection rate, days to heading, plant height, number of fertile tillers per plant, seeds per spike, spike length and thousand seed weight. The overall mean net blotch epidemics varied from area under disease progress curve (AUDPC) of 86 to 1835. The disease was as high as AUDPC of 1378 on the susceptible check ‘Abdanie’. Similarly, the variations between and within barley landraces in terms of regions of origin, altitude classes and ear-types were significant. Out of the 585 barley landraces evaluated, 198 (33.85%) had significantly lower disease than the susceptible check, of which 12 (2.05%) and 186 (31.79%) landraces, respectively showed resistant (R) and moderately resistant (MR) infection types. The frequency of resistant landraces was more in third (2000-2500 m) and fourth (>2500 m) altitude classes and six-rowed and irregular barley types than in lower altitude areas and two-rowed ear-types. Furthermore, the correlation analysis among PSI and some yield components revealed adverse effect of the disease on grain yield of barley.
Ethiopian barley landraces are recognized as an important genetic resource with which a search fo... more Ethiopian barley landraces are recognized as an important genetic resource with which a search for tolerance to biotic stresses is of worth. In present study, 585 barley ( Hordeum vulgare L.) landraces collected from 13 barley producing zones of Ethiopia were evaluated along with 10 improved checks for resistance to BYDV serotype PAV under field conditions at Sinana and Goba during 2018 and 2019 cropping seasons. The trial was laid out in an augmented design consisting of six blocks. Data on disease incidence, severity and some agronomic traits were recorded. The result of analysis showed highly significant variations among landraces for disease incidence, severity and agronomic traits. The BYDV incidence and severity varied from 0.90 to 45.3% and 12.0 to 58.0%, respectively. Similarly, significant variations in terms of regions of origin, altitude classes and kernel row number were observed among landraces. Landraces originated from Arsi, Gojam, Bale and Gonder had significantly lower disease incidence and severity levels than others. Furthermore, landraces collected from altitude class IV (above 2500 m) and those with 6-row and irregular kernel type had lower disease severity. Segregation in infection was observed in some landraces due to a reduction of disease severity and 68 landraces showing lowest disease severity were selected. The resistant landraces identified in the present investigation can be utilized as good resource for barley improvement program targeting BYDV, which subsequently will help to incorporate the resistant genes into several elite backgrounds of barley.
The main germplasm resource bases used for genetic diversity in disease resistance include wild a... more The main germplasm resource bases used for genetic diversity in disease resistance include wild ancestral species, landraces and commercial varieties. In this study, 585 barley ( Hordeum vulgare L.) landraces were evaluated along with 10 checks for resistance to leaf rust ( P. hordei ) pathotype ETPh7611 under field conditions at Sinana and Goba, Ethiopia, during 2018 and 2019 main cropping seasons. The trial was laid out in augmented design consisting of six blocks and each plot comprised a single row of 1.75 m long and 0.2 m spacing between rows. Data on disease incidence, severity and agronomic traits were recorded. The result showed highly significant variations among landraces for disease incidence, severity, and agronomic traits. The leaf rust incidence and AUDPC varied from 63.7 to 86.3 and 651.5 to 2096.4, respectively. Similarly, the variations among landraces in terms of regions of origin, altitude classes, and kernel row number were significant. Landraces originated from Arsi, Bale and Gonder had significantly lower disease incidence and severity than others. Furthermore, landraces collected from altitude class III (2000–2,500 m) and those with 2-row and irregular kernel type had lower disease severity. Segregation in infection type as well as partial resistance (PR) was observed in some landraces due to a reduction of disease severity and 33 landraces showing lowest disease severity were selected. The resistant landraces identified in the present investigation can be utilized to study the genetics of resistance to leaf rust resistance, which subsequently will help to incorporate the resistant genes into several elite backgrounds of barley.
Garlic is one of the most crucial Allium vegetables used as seasoning of foods. It has a lot of b... more Garlic is one of the most crucial Allium vegetables used as seasoning of foods. It has a lot of benefits from the medicinal and nutritional point of view; however, its production is highly constrained by both biotic and abiotic challenges. Among these, viral infections are the most prevalent factors affecting crop productivity around the globe. This experiment was conducted on eleven selected garlic accessions and three improved varieties collected from different garlic growing agro-climatic regions of Ethiopia. This study aimed to identify and characterize the isolated garlic virus using the coat protein (CP) gene and further determine their phylogenetic relatedness. RNA was extracted from fresh young leaves, thirteen days old seedlings, which showed yellowing, mosaic, and stunting symptoms. Pairwise molecular diversity for CP nucleotide and amino acid sequences were calculated using MEGA5. Maximum Likelihood tree of CP nucleotide sequence data of Allexivirus and Potyvirus were con...
International Journal of Advanced Research in Biological Sciences (IJARBS), 2020
Landraces play a key role in crop breeding by providing beneficial trait for improvement of relat... more Landraces play a key role in crop breeding by providing beneficial trait for improvement of related crops and their genetic diversity studies are very important for breeding program and identification of parental lines. In this study, 585 barley (Hordeum vulgare L.) landraces collected from 13 agro-ecological zones of Ethiopia were evaluated along with 10 cultivars for their phenotypic diversity and population structure in relation to agronomic traits, resistance to major diseases and barley shoot fly. Data on 22 agronomic traits, three major diseases and barley shoot fly resistance-related traits were recorded. Univariate and multivariate approaches such as principal component and cluster analyses were applied to assess the genetic diversity and population structure. The analysis of variance indicated significant genotypic main, accessions x year and accession x environment interaction effects for almost all the traits evaluated. However, the accessions x environment interactions w...
The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has r... more The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has recently become an invasive insect pest in China. Because of its rapid spread and great risks in China, understanding of FAW genetic background and pesticide resistance is urgent and essential to develop effective management strategies. Here, we assembled a chromosome-level genome of a male FAW (SFynMstLFR) and compared re-sequencing results of the populations from America, Africa, and China. Strain identification of 163 individuals collected from America, Africa and China showed that both C and R strains were found in the American populations, while only C strain was found in the Chinese and African populations. Moreover, population genomics analysis showed that populations from Africa and China have close relationship with significantly genetic differentiation from American populations. Taken together, FAWs invaded into China were most likely originated from Africa. Comparative genomics...
Barley shoot fly ( Delia flavibasis ) is one of the destructive insect pests of barley ( Hordeum ... more Barley shoot fly ( Delia flavibasis ) is one of the destructive insect pests of barley ( Hordeum vulgare L.) at seedling stage. Resistance to barley shoot fly is governed by complex traits that derived from both morphological and/or biochemical characters of the plant. These host plant characters influence the relative degree of damage caused by the insect. The study aimed to evaluate phenotypic variability and interrelationships of factors influencing barley shoot fly resistance. Five hundred eighty-five landraces and ten cultivars were tested at Sinana Agricultural Research Center on station and Goba on-farm, during 2018 and 2019 main cropping seasons using augmented design consisting six blocks. High heritability percentage was obtained for yield and shoot fly resistance components like biomass (95.38%), early seedling growth vigour (91.41%), total tillers plant −1 (89.41%), fertile tiller plant −1 (88.91%), seedling colour (85.36), plant height (82.83%), 1000 seed weight (82.53%), number of seeds spike −1 (81.80%), spike length (81.11%), oviposition (65.74%) and dead heart (61.26%). Thus, this study revealed the presence of sufficient variability among the barley landraces in the country that can be exploited for germplasm enhancement. Furthermore, the defensive characters of accessions for shoot fly strongly influence the oviposition and dead heart percentage.
The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The... more The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it. In particular, we characterize female gland extracts and headspace samples through coupled gas chromatography electro-antennographic detection (GC-EAD) and two dimensional gas chromatography mass spectrometry (GCxGC-MS). Tentative identities of the potential pheromone compounds were confirmed by comparing both retention time and mass spectra with authentic standards. Two electrophysiologically active pheromone compounds, tetradecyl acetate (14:OAc) and Z9-tetradecenyl acetate (Z9-14:OAc) were identified from pheromone gland extracts, and an additional compound (Z9-1...
ABSTRACT Strain selection based on temperature may be warranted when choosing an isolate for deve... more ABSTRACT Strain selection based on temperature may be warranted when choosing an isolate for development as a microbial control agent. To this end, the effects of three temperature regimes, namely 20, 25 and 30°C, on the virulence of four Beauveria and two Metarhizium isolates against the cotton aphid, Aphis gossypii, were investigated under controlled conditions, 65–70% relative humidity, and a photoperiod of 12:12 (light: dark) hours. The isolates did vary significantly in their activities of efficacy over a range of temperatures. The highest mortality and lowest survival times were observed at 25°C for DLCO41 and at 30°C for DLCO87; while mortality decreased and survival time increased at temperatures of 20°C. Besides the tested fungal isolate DLCO87 had the lowest LC50 value (6.84 × 10 5 conidia mL−1) at 30°C. The promising result of this study should enable us to conduct further studies to determine the potential use of the fungus as an agent against Aphis gossypii both in greenhouse and under field conditions.
Background Ethiopia is considered as center of diversity for barley (Hordeum vulgare L.) and it i... more Background Ethiopia is considered as center of diversity for barley (Hordeum vulgare L.) and it is grown across different agro-ecologies of the country. Unraveling population structure and gene flow status on temporal scales assists an evaluation of the consequences of physical, demographic and overall environmental changes on the stability and persistence of populations. This study was to examine spatial and temporal genetic variation within and among barley landrace samples collected over a period of four decades, using simple sequence repeat markers. Results Results from STRUCTURE, neighbor joining tree and discriminant analysis of principal component (DAPC) analysis revealed presence low-to-high genetic diversity among the landraces and grouped the landraces into three clusters. The cluster analysis revealed a close relationship between landraces along geographic proximity with genetic distance increases along with geographic distance. From analysis of molecular variance (AMOVA)...
In this study, we evaluated a collection of 585 barley landraces along with 10 checks at Sinana A... more In this study, we evaluated a collection of 585 barley landraces along with 10 checks at Sinana Agricultural Research Center (SARC) and Bale-Goba research sites in 2018/19 and 2019/20 cropping seasons for resistance to net blotch (Pyrenophora teres F. teres (Ptt)). The experiments were laid out in an augmented complete block design. Data on agronomic performance and disease response were recorded. Analysis of variance showed highly significant variations between and within the landraces and cultivars in net blotch percent severity index (PSI), area under the disease progress curve (AUDPC), apparent infection rate, days to heading, plant height, number of fertile tillers per plant, seeds per spike, spike length and thousand seed weight. The overall mean net blotch epidemics varied from area under disease progress curve (AUDPC) of 86 to 1835. The disease was as high as AUDPC of 1378 on the susceptible check ‘Abdanie’. Similarly, the variations between and within barley landraces in terms of regions of origin, altitude classes and ear-types were significant. Out of the 585 barley landraces evaluated, 198 (33.85%) had significantly lower disease than the susceptible check, of which 12 (2.05%) and 186 (31.79%) landraces, respectively showed resistant (R) and moderately resistant (MR) infection types. The frequency of resistant landraces was more in third (2000-2500 m) and fourth (>2500 m) altitude classes and six-rowed and irregular barley types than in lower altitude areas and two-rowed ear-types. Furthermore, the correlation analysis among PSI and some yield components revealed adverse effect of the disease on grain yield of barley.
Ethiopian barley landraces are recognized as an important genetic resource with which a search fo... more Ethiopian barley landraces are recognized as an important genetic resource with which a search for tolerance to biotic stresses is of worth. In present study, 585 barley ( Hordeum vulgare L.) landraces collected from 13 barley producing zones of Ethiopia were evaluated along with 10 improved checks for resistance to BYDV serotype PAV under field conditions at Sinana and Goba during 2018 and 2019 cropping seasons. The trial was laid out in an augmented design consisting of six blocks. Data on disease incidence, severity and some agronomic traits were recorded. The result of analysis showed highly significant variations among landraces for disease incidence, severity and agronomic traits. The BYDV incidence and severity varied from 0.90 to 45.3% and 12.0 to 58.0%, respectively. Similarly, significant variations in terms of regions of origin, altitude classes and kernel row number were observed among landraces. Landraces originated from Arsi, Gojam, Bale and Gonder had significantly lower disease incidence and severity levels than others. Furthermore, landraces collected from altitude class IV (above 2500 m) and those with 6-row and irregular kernel type had lower disease severity. Segregation in infection was observed in some landraces due to a reduction of disease severity and 68 landraces showing lowest disease severity were selected. The resistant landraces identified in the present investigation can be utilized as good resource for barley improvement program targeting BYDV, which subsequently will help to incorporate the resistant genes into several elite backgrounds of barley.
The main germplasm resource bases used for genetic diversity in disease resistance include wild a... more The main germplasm resource bases used for genetic diversity in disease resistance include wild ancestral species, landraces and commercial varieties. In this study, 585 barley ( Hordeum vulgare L.) landraces were evaluated along with 10 checks for resistance to leaf rust ( P. hordei ) pathotype ETPh7611 under field conditions at Sinana and Goba, Ethiopia, during 2018 and 2019 main cropping seasons. The trial was laid out in augmented design consisting of six blocks and each plot comprised a single row of 1.75 m long and 0.2 m spacing between rows. Data on disease incidence, severity and agronomic traits were recorded. The result showed highly significant variations among landraces for disease incidence, severity, and agronomic traits. The leaf rust incidence and AUDPC varied from 63.7 to 86.3 and 651.5 to 2096.4, respectively. Similarly, the variations among landraces in terms of regions of origin, altitude classes, and kernel row number were significant. Landraces originated from Arsi, Bale and Gonder had significantly lower disease incidence and severity than others. Furthermore, landraces collected from altitude class III (2000–2,500 m) and those with 2-row and irregular kernel type had lower disease severity. Segregation in infection type as well as partial resistance (PR) was observed in some landraces due to a reduction of disease severity and 33 landraces showing lowest disease severity were selected. The resistant landraces identified in the present investigation can be utilized to study the genetics of resistance to leaf rust resistance, which subsequently will help to incorporate the resistant genes into several elite backgrounds of barley.
Garlic is one of the most crucial Allium vegetables used as seasoning of foods. It has a lot of b... more Garlic is one of the most crucial Allium vegetables used as seasoning of foods. It has a lot of benefits from the medicinal and nutritional point of view; however, its production is highly constrained by both biotic and abiotic challenges. Among these, viral infections are the most prevalent factors affecting crop productivity around the globe. This experiment was conducted on eleven selected garlic accessions and three improved varieties collected from different garlic growing agro-climatic regions of Ethiopia. This study aimed to identify and characterize the isolated garlic virus using the coat protein (CP) gene and further determine their phylogenetic relatedness. RNA was extracted from fresh young leaves, thirteen days old seedlings, which showed yellowing, mosaic, and stunting symptoms. Pairwise molecular diversity for CP nucleotide and amino acid sequences were calculated using MEGA5. Maximum Likelihood tree of CP nucleotide sequence data of Allexivirus and Potyvirus were con...
International Journal of Advanced Research in Biological Sciences (IJARBS), 2020
Landraces play a key role in crop breeding by providing beneficial trait for improvement of relat... more Landraces play a key role in crop breeding by providing beneficial trait for improvement of related crops and their genetic diversity studies are very important for breeding program and identification of parental lines. In this study, 585 barley (Hordeum vulgare L.) landraces collected from 13 agro-ecological zones of Ethiopia were evaluated along with 10 cultivars for their phenotypic diversity and population structure in relation to agronomic traits, resistance to major diseases and barley shoot fly. Data on 22 agronomic traits, three major diseases and barley shoot fly resistance-related traits were recorded. Univariate and multivariate approaches such as principal component and cluster analyses were applied to assess the genetic diversity and population structure. The analysis of variance indicated significant genotypic main, accessions x year and accession x environment interaction effects for almost all the traits evaluated. However, the accessions x environment interactions w...
The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has r... more The fall armyworm (FAW), Spodoptera frugiperda, is a destructive pest native to America and has recently become an invasive insect pest in China. Because of its rapid spread and great risks in China, understanding of FAW genetic background and pesticide resistance is urgent and essential to develop effective management strategies. Here, we assembled a chromosome-level genome of a male FAW (SFynMstLFR) and compared re-sequencing results of the populations from America, Africa, and China. Strain identification of 163 individuals collected from America, Africa and China showed that both C and R strains were found in the American populations, while only C strain was found in the Chinese and African populations. Moreover, population genomics analysis showed that populations from Africa and China have close relationship with significantly genetic differentiation from American populations. Taken together, FAWs invaded into China were most likely originated from Africa. Comparative genomics...
Barley shoot fly ( Delia flavibasis ) is one of the destructive insect pests of barley ( Hordeum ... more Barley shoot fly ( Delia flavibasis ) is one of the destructive insect pests of barley ( Hordeum vulgare L.) at seedling stage. Resistance to barley shoot fly is governed by complex traits that derived from both morphological and/or biochemical characters of the plant. These host plant characters influence the relative degree of damage caused by the insect. The study aimed to evaluate phenotypic variability and interrelationships of factors influencing barley shoot fly resistance. Five hundred eighty-five landraces and ten cultivars were tested at Sinana Agricultural Research Center on station and Goba on-farm, during 2018 and 2019 main cropping seasons using augmented design consisting six blocks. High heritability percentage was obtained for yield and shoot fly resistance components like biomass (95.38%), early seedling growth vigour (91.41%), total tillers plant −1 (89.41%), fertile tiller plant −1 (88.91%), seedling colour (85.36), plant height (82.83%), 1000 seed weight (82.53%), number of seeds spike −1 (81.80%), spike length (81.11%), oviposition (65.74%) and dead heart (61.26%). Thus, this study revealed the presence of sufficient variability among the barley landraces in the country that can be exploited for germplasm enhancement. Furthermore, the defensive characters of accessions for shoot fly strongly influence the oviposition and dead heart percentage.
The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The... more The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it. In particular, we characterize female gland extracts and headspace samples through coupled gas chromatography electro-antennographic detection (GC-EAD) and two dimensional gas chromatography mass spectrometry (GCxGC-MS). Tentative identities of the potential pheromone compounds were confirmed by comparing both retention time and mass spectra with authentic standards. Two electrophysiologically active pheromone compounds, tetradecyl acetate (14:OAc) and Z9-tetradecenyl acetate (Z9-14:OAc) were identified from pheromone gland extracts, and an additional compound (Z9-1...
ABSTRACT Strain selection based on temperature may be warranted when choosing an isolate for deve... more ABSTRACT Strain selection based on temperature may be warranted when choosing an isolate for development as a microbial control agent. To this end, the effects of three temperature regimes, namely 20, 25 and 30°C, on the virulence of four Beauveria and two Metarhizium isolates against the cotton aphid, Aphis gossypii, were investigated under controlled conditions, 65–70% relative humidity, and a photoperiod of 12:12 (light: dark) hours. The isolates did vary significantly in their activities of efficacy over a range of temperatures. The highest mortality and lowest survival times were observed at 25°C for DLCO41 and at 30°C for DLCO87; while mortality decreased and survival time increased at temperatures of 20°C. Besides the tested fungal isolate DLCO87 had the lowest LC50 value (6.84 × 10 5 conidia mL−1) at 30°C. The promising result of this study should enable us to conduct further studies to determine the potential use of the fungus as an agent against Aphis gossypii both in greenhouse and under field conditions.
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Papers by Dawit Degefu