Query: wheat stem rust in Ethiopia 2000-2020

title: Spatiotemporal hotspot patterns of wheat rust incidence and severity in Ethiopia
abstract: Wheat rusts, stem rust, leaf rust, and stripe or yellow rust are the major biotic constraints in all wheat growing regions of Ethiopia. Therefore, the main objective of this study is to identify the temporal spatial hot spot pattern of wheat rust incidence and severity in Ethiopia. A GIS based hotspot analysis tool was employed to identify the spatial distribution of hot spot patterns and temporal trends using survey data collected by the International Maize and Wheat Improvement Center and the Ethiopian Institute of Agricultural Research from the fields of smallholder farmers in Ethiopia. The analysis identified seven hot spot pattern categories; no trend detected, new hot spot, consecutive hot spot, diminishing hot spot, oscillating hot spot, persistent hot spot and a sporadic hot spot for yellow and stem rusts distributed in different parts of the country. For instance, the persistent hot spot is observed in west Arsi and Bale zones, which are the potential wheat growing areas of the country while new hot spots are emerging in central and northern parts of the country. Generally, areas where these two hot spot patterns occurred, are requiring special attention to minimize yield loss due to rust and tackle food insecurity.  Emerging hotspot, stem rust, yellow rust, leaf rust.

title: Varieties Reaction for Wheat Rust Diseases in Hadiya Zone, Ethiopia
abstract: Wheat is an important cereal crop in Ethiopia that is widely cultivated in a wide range of altitude. It ranks fourth in area coverage and total production after teff, maize and sorghum. Hadiya Zone is one of the major wheat producing areas in Ethiopia and it is recognized as one of the wheat belts in the country. But wheat production is threatened by abiotic and biotic constraints. Among the biotic, wheat rust (stem rust, yellow rust and stripe rust) is one of the major limitations of wheat production. Even though, Hadiya zone is known in wheat production, there is no detailed information regarding the distribution, incidence and severity of wheat rust. Therefore, this study was conducted with the following objective: to assess the reaction of varieties against wheat rust. The survey was conducted in 2017main cropping season from mid September to mid October in three districts of Hadiya zone (Misha, Lemo and Duna) A total of 72 fields were surveyed at every 5 to 10 km using vehicle odometer along the main and accessible road sides. The plant samples with in a selected field were taken in X fashion using 0.5m X 0.5m (0.25m 2 quadrates. Reaction of wheat varieties to stem rust ranges from 5.5% 16 The lowest severity of stem rust was recorded on variety Digalu (5.5% where as the highest was from local variety (16% In general, disease severity was classified under low class. The survey work showed that if susceptible improved and local cultivars continue to grow as mono cropping system (due to strategy of cluster farming) serious wheat rust epidemics may occur in the zones and may cause high economic loss. Therefore, it is advised to device other farming system instead of cluster farming and replacing of susceptible varieties with new resistant varieties.

title: Assessment of Sources of Adult Plant Resistance Genes to Stem Rust in Ethiopian Durum Wheat Genotypes
abstract: Stem rust is a devastating disease of bread wheat and durum wheat in the major wheat growing regions of the world. Races belonging to the Ug99 (TTKSK) lineage of the wheat stem rust fungus, carrying complex virulence combinations, and their migration to countries in Africa, Middle East and Asia continue to pose a significant threat to global wheat production. Therefore, the present study was conducted in the greenhouse and field to assess sources of durable resistance to stem rust. Fifteen durum wheat genotypes and a susceptible cultivar 'Morocco' were evaluated in the greenhouse and field at Debre Zeit Agricultural Research Center, Ethiopia in order to detect the presence of effective stem rust resistance genes. A mixture of three dominant races of Puccinia graminis f. sp. tritici (TKTTF, TTKSK and JRCQC) was used for inoculation. The field experiment was conducted using RCB design with three replications at two different locations. Phenotyping of the genotypes at seedling stage in the greenhouse showed four genotypes (Ginchi, Quami, DW #3 and DW #11) that carried effective ASR genes; however, the rest eleven genotypes showed susceptible reaction. On the other hand, the field assessment of the genotypes for stem rust resistance showed presence of varied levels of field resistance. The combined results from both seedling reaction test and field experiments indicated that the eleven genotypes might possess one or more adult plant resistance (APR) genes to stem rust of wheat. Molecular marker analysis for detection of the known APR genes (Sr2, Sr55, Sr56, Sr57, and Sr58) should be conducted along with multi pathotype tests for further determination of the specific genes(s) that conferred resistance to stem rust pathogen races including Ug99 and its derivatives for each genotype. The eleven genotypes that possessed APR genes can be good sources of durable stem rust resistance genes to be incorporated in the Ethiopian durum wheat improvement program

title: Impact of Climate Variability and Its Related Disease Prevalence on the Yield of Winter Wheat (Triticum Aestivum Lam) in South East Ethiopia
abstract: Impacts of climate variability and disease prevalence on crop productivity (particularly wheat yield) are becoming major concern on their stable supply that affecting the livelihood of the farmers and consumers in South East Ethiopia. The study was carried out with general objective to examine the effect of precipitation, temperature variation and disease prevalence on winter wheat (Triticum Aestivum Lam) for the last 20 years in Sinana farm of Oromia Seed Enterprise south east Ethiopia. Temperature and precipitation trends were evaluated using Sen's slope estimator and Mann Kendall trend test methods. The Pearson's correlation coefficient was used to measure the strength of the association between crop yield and climatic variability. Predictor models on productivity status comprising disease prevalence associated to climate variability for 20 years were established. A1degC temperature rise in average seasonal maximum temperature above the optimum brought productivity reduction by 1.17% coefficient of determination R2=0.428. Further, in 1degC temperature rise, the regression analysis of the productivity related to stem rust prevalence was subjected to a positive impact under Tmin, Tmax, RH, and seasonal RF with coefficient of determination R2=0.756. On the other hand, yellow rust prevalence was positively correlated with minimum temperature, maximum temperature and average relative humidity, but it was negatively correlated with average seasonal temperature. The study concluded that the variability of climate elements has been exerting a huge impact on the quality and quantity of winter wheat.

title: Analysis of Climate Variability Effects on Wheat Stem Rust Puccinia graminis f.sp tritici Epidemics in Bale and Arsi Zones of Oromia Regional State, Ethiopia
abstract: Stem rust caused by Puccinia graminis f.sp tritici is the most destructive disease of wheat in the world. Bale and Arsi zones are conducive for stem rust epidemics. The study was conducted in 2013 to assess and model the effect of climate variability on wheat stem rust epidemics. The meteorological and disease data for the year 2004 to 2013 of Sinana and Kulumsa were obtained from the respective research centers and were analyzed. Four bread wheat cultivars, namely Kubsa, Madawalabu, Sofumer and Tusie were included in the study. The present study showed that stem rust epidemics was higher at kulumsa than at Sinana over the last 10 years. The increased stem rust severity at Sinana and Kulumsa were due to the total seasonal rainfall increase during wheat growing seasons. A reduction in stem rust severity was manifested at Sinana and kulumsa as seasonal mean minimum temperature increased, whereas a reduction in stem rust severity occurred at Kulumsa as the seasonal average relative humidity increased. The total seasonal rainfall had positive effect on the development of wheat stem rust, while the seasonal mean minimum temperature and seasonal average relative humidity significantly affected the development of wheat stem rust in the field.

title: Significance of Wheat Stem Rust (Puccinia graminis f.sp. tritici) in Gurage Zone, Ethiopia
abstract: Wheat is one of the important cereal crops of Ethiopia. It is the leading crop in land coverage and total production next to tef and maize and in productivity after maize and sorghum. Gurage highlands are also considered to be suitable areas for wheat production in the country. However, the production of wheat in this region is threatened by different wheat rusts; such as stem rust disease. So, this study was conducted with the following objectives: to determine distribution, incidence and severity of wheat stem rust in Gurage highlands. Field survey was carried out in four districts of Gurage zone. A total of 100 fields were surveyed. During survey stem rust disease was occurred in 88% of the fields surveyed in Gurage zone. The mean incidence of pathogen was 47.45% The highest mean severity (20.68% was recorded in Soddo followed by Cheha (12.84% All varieties grown in the zone were attacked by the disease in one area or the other. Though, the degree of incidence and severity was varied. Varieties such as Digelu, Kenya, and Pavon76 were found to be severely affected by the pathogen. In conclusion, the survey revealed high occurrence and distribution of wheat stem rust in the study areas. Therefore, it is very important for the Ethiopian Institute for Agricultural Research, especially national wheat research program to replace these susceptible varieties with currently effective resistance genes. Additionally, it is also better to monitor pathogen distribution and populations over time to track further virulence evolution and to ensure that currently effective resistance genes are applied within a system of resistance gene management.

title: Pathogenic Variability of Wheat Stem Rust Pathogen (Puccinia graminis f. sp. tritici) in Hararghe Highlands, Ethiopia
abstract: Wheat is one of the important major crops of Hararghe Highlands. It is third in land coverage and total production after sorghum and maize. However, the wheat stem rust disease is threatening production of wheat in this region. So, this research was conducted with the following objective: to determine the population of Puccinia graminis f. sp. tritici in Hararghe Highlands. A total of 200 fields were surveyed and stem rust samples were collected and transported to Kulumsa Agricultural Research Center for race analysis. Inoculation of differentials carrying resistance genes Sr24 and Sr Tmp indicated typical low infection types on all isolates. Isolates EH5, EH8, and EH3 from East Hararghe and WH2, WH1, and WH3 from West Hararghe showed high virulence of infection in all differential lines. Ten (10) races were identified by using Puccinia graminis tritici code system: TTGSK, PTJQK, TTSSK, TTKSK, TRSSK, and TTJQK from East Hararghe and TTTSK and TTSQK from West Hararghe zones. Race TTSSK was most frequent (25% followed by TTKSK (25% in East Hararghe. Race TTSSK showed 50% frequency of occurrence in West Hararghe zones. The low frequency of occurrences indicated high variability of the races in the survey areas. Therefore, monitoring of populations of pathogens is important for the national and regional research centers. Detection of pathogen virulence evolution and of currently effective resistance genes is necessary and must be applied within a system of resistance gene management.

title: Effects of Stem Rust Puccinia graminis f.sp. tritici on Yield, Physical and Chemical Quality of Durum Wheat Varieties in East Shoa Zone, Ethiopia
abstract: Stem rust or black rust caused by Puccinia graminis f.sp. tritici is one of the major biotic constraints of wheat production in Ethiopia. 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 and qualitative losses are often overlooked. As the result, the current research was designed with the objective of elucidating the effect of wheat stem rust on yield, physical and processing quality of durum wheat. For this purpose, a factorial field experiment involving three durum wheat varieties (Ude, Denbi and Hitosa) were selected and Tilt application was conducted at Debre Zeit Agricultural Research Centre for two cropping seasons (2016 2017) The experiment was laid out in randomized complete block design with three replications and untreated checks were included for comparison purpose. Results revealed significant variations in disease parameters and crop performance of treated plots, wheat varieties and their interactions. Stem rust severity was significantly reduced by the application of Tilt across all wheat varieties, and the highest decrease in disease level (8.9 and 15.2% was achieved by Tilt application in 2017 and 2016 cropping seasons, respectively. Correlation analysis revealed negative relationship between stem rust and durum wheat grain yield and quality parameters, which was highly significant in most cases. However, there was highly significantly positive correlation (r=0.31* and r 0.39* between stem rust and grain protein content during the year of 2016 and 2017 cropping seasons, respectively. The results confirmed the economic importance of stem rust to food industry for its effect on grain yield, physical and processing quality of durum wheat in Ethiopia.

title: Large Scale Atmospheric Dispersal Simulations Identify Likely Airborne Incursion Routes of Wheat Stem Rust Into Ethiopia.
abstract: In recent years, severe wheat stem rust epidemics hit Ethiopia, sub Saharan Africa's largest wheat producing country. These were caused by race TKTTF (Digalu race) of the pathogen Puccinia graminis f. sp. tritici, which, in Ethiopia, was first detected at the beginning of August 2012. We use the incursion of this new pathogen race as a case study to determine likely airborne origins of fungal spores on regional and continental scales by means of a Lagrangian particle dispersion model (LPDM) Two different techniques, LPDM simulations forward and backward in time, are compared. The effects of release altitudes in time backward simulations and P. graminis f. sp. tritici urediniospore viability functions in time forward simulations are analyzed. Results suggest Yemen as the most likely origin but, also, point to other possible sources in the Middle East and the East African Rift Valley. This is plausible in light of available field surveys and phylogenetic data on TKTTF isolates from Ethiopia and other countries. Independent of the case involving TKTTF, we assess long term dispersal trends >10 years) to obtain quantitative estimates of the risk of exotic P. graminis f. sp. tritici spore transport (of any race) into Ethiopia for different 'what if' scenarios of disease outbreaks in potential source countries in different months of the wheat season.

title: Sources of Resistance to Stem Rust (Puccinia graminis f. sp. tritici) in Improved Durum Wheat (Triticum turgidum l. Varieties of Ethiopia
abstract: Article History Received: 6 September 2019  8 October 2019  12 November 2019