Maize and Wheat; Strategic crops to fill Ethiopia's food basket

Poster prepared for a share fair, Addis Ababa, May 201

Virulence Spectrum of Puccinia graminis f. sp. tritici in Northwest Ethiopia

 አህፅሮትኢትዮጵያ ውስጥ ስንዴን ከሚያጠቁ በሽታዎች መካከል የግንድ ዋግ አንዱ እና ዋነኛው ነው፡፡ ይህንን በሽታ የሚያመጣው ተዋስያን አካል የአየሩን ምቹ ሁኔታ በመጠቀም እራሱን እየቀያየረ በሽታ የሚቋቋሙ የስንዴ ዝርያዎችን በማጥቃት ከፍተኛ የሆነ የምርት ቅነሳ ያደርጋል፡፡ የዚህ ጥናት ዓላማ የነበረው በሰሜን ምዕራብ ኢትዮጵያ ውስጥ ያለውን የስንዴ የግንድ ዋግ ዝርያ መለየት ነው፡፡ ሰማንያ ስድስት ናሙናዎች በ2010 እና በ2011 የምርት ዘመን ተሰብስበው 20 ድፍሬንሻሎችን በመጠቀም አራት (TTTTF, TKTTF, TKPTF, and TTRTF) የስንዴ ግንድ ዋግ ዝርያዎችን ለመለየት ተችሏል፡፡ ከእነዚህ አራት ዝርያዎች ውስጥ በ2010ና በ2011 በተከታታይ በአማካይ በመቶኛ TTTTF 60.4 እና 60 የሚሆነውን የሚሸፍን ሲሆን በሁለተኛነት ደረጃ TKTTF 38.7 እና 37.3 ሸፍኖ ታይቷል፡፡ ሌሎች የግንድ ዋግ ዝርያዎች በሁለቱም የምርት ዘመን በአማካይ በመቶኛ 1 የሚሆነውን የሸፈኑ ሲሆን እነዚህ ሁለት ዝርያዎች የተገኙትም፤ TKPTF በ2010 ከደቡብ ጎንደር ፋርጣ ሲሆን TTRTF በ2011 ከሰሜን ጎንደር አምባ ጊዎርጊስ ላይ ብቻ ነው፡፡ የግንድ ዋግ የሚቋቋሙ ዘረመልን የያዙ ድፍሬንሻሎች እንደ Sr5, Sr21, Sr9e, Sr7b, Sr6, Sr8a, Sr9g, Sr36, Sr17, Sr9a, Sr9d, Sr10, SrTmp, Sr38 እና SrMcN ሁሉም በተለዩ የዋግ ዝርያዎች የተጠቁ ሲሆን Sr24 እና Sr31 ዋግ የሚቋቋሙ ዘረመልን የያዙ ድፍሬንሻሎች ግን ሙሉ በሙሉ የተለዩትን የዋግ ዝርያዎችን መቋቋም ችለዋል፡፡ በአሁኑ ጥናት Sr31  እና በአሁኑና ከዚህ በፊት ኢትዮጵያ ውስጥ በተደረጉ ጥናቶች Sr24  ዘረመልን የሚያጠቃ የግንድ ዋግ ዝርያ ያለመኖሩ ስለተረጋገጠ  እነዚህን ዘረመሎች ከሌሎች የግንድ ዋግ መቆጣጠሪያ መንገዶች ጋር በመጠቀም አሁን ያለውን የግንድ ዋግ ዝርያ መቋቋም የሚችል የስንዴ ዝርያ ማዳቀል ይቻላል፡፡ AbstractStem rust caused by Puccinia graminis f. sp. tritici is one of the most important diseases of wheat in Ethiopia. The pathogen can produce new races that can overcome resistant varieties and cause epidemic under favorable environmental conditions resulting in serious yield losses. The study was carried out to determine the virulence spectrum of Puccinia graminis f. sp. tritici in northwest Ethiopia. Eighty-six stem rust samples were collected during 2017 and 2018 cropping seasons and analyzed on 20 standard stem rust differential lines which resulted in the identification of four races (TTTTF, TKTTF, TKPTF, and TTRTF). Of these races, 60.4 and 60% of the isolates were TTTTF followed by 38.7 and 37.3% of TKTTF (Digalu race) in 2017 and 2018, respectively.  These two races accounted for almost 99% of the stem rust population. The least virulent races were TKPTF and TTRTF that accounted 1% in both seasons and were detected only at single location (Farta in South Gondar in 2017 and Amba Giorgis in North Gondar in 2018). The differential hosts carrying resistance genes Sr5, Sr21, Sr9e, Sr7b, Sr6, Sr8a, Sr9g, Sr36, Sr17, Sr9a, Sr9d, Sr10, SrTmp, Sr38 and SrMcN were susceptible to the four races identified in northwest Ethiopia. Two differential hosts carrying the resistant genes Sr24 and Sr31 were effective against all the four races identified in this study. Absence of virulence against lines carrying Sr31 in the present and Sr24 in the present and previous studies suggests that these genes may serve as a source of resistance in combination with other wheat stem rust management systems to the current rust races in northwest Ethiopia

Genome-wide association mapping for grain shape and color traits in Ethiopian durum wheat (Triticum turgidum ssp. durum)

Abstract Grain shape and color strongly influence yield and quality of durum wheat. Identifying QTL for these traits is essential for transferring favorable alleles based on selection strategies and breeding objectives. In the present study, 192 Ethiopian durum wheat accessions comprising 167 landraces and 25 cultivars were genotyped with a high-density Illumina iSelect 90 K single-nucleotide polymorphism (SNP) wheat array to conduct a genome-wide association analysis for grain width (GW), grain length (GL), CIE (Commission Internationale l'Eclairage) L* (brightness), CIE a* (redness), and CIE b* (yellowness) traits. The accessions were planted at Sinana Agricultural Research Center, Ethiopia in the 2015/2016 cropping season in a complete randomized block design with three replications. Twenty homogeneous and healthy seeds per replicate were used for trait measurement. Digital image analysis of seeds with GrainScan software package was used to generate the phenotypic data. Analysis of variance revealed highly significant differences between accessions for all traits. A total of 46 quantitative trait loci (QTL) were identified for all traits across all chromosomes. One novel major candidate QTL (−lg P ≥ 4) with pleiotropic effects for grain CIE L* (brightness) and CIE a* (redness) was identified on the long arm of chromosome 2A. Eighteen nominal QTL (−lg P ≥ 3) and 26 suggestive QTL (−lg P ≥ 2.5) were identified. Pleiotropic QTL influencing both grain shape and color were identified

Nitrogen deficiency tolerance and responsiveness of durum wheat genotypes in Ethiopia

Development of low-nitrogen (N) tolerant and N-responsive durum wheat genotypes is required since nitrogen efficiency has emerged as a highly desirable trait from economic and environmental perspectives. Two hundred durum wheat genotypes were evaluated at three locations under optimum (ON) and low (LN) nitrogen conditions to screen genotypes for low-nitrogen tolerance and responsiveness to an optimum N supply. The results showed significant variations among the durum wheat genotypes for low-N tolerance and responsiveness. The average reduction in grain yield under the LN condition was 48.03% across genotypes. Only 17% of the genotypes tested performed well (grain yield reduction <40%) under LN conditions. Based on the absolute grain yield, biomass yield, and normalized difference vegetative index value, on average, 32, 14, 17, and 37% of the tested genotypes were classified as efficient and responsive, efficient and nonresponsive, inefficient and responsive, and inefficient and nonresponsive, respectively. Considering the absolute and relative grain yield, biomass yield, normalized difference vegetative index values, and stress tolerance indices as selection criteria, 17 genotypes were chosen for subsequent breeding. Among the screening indices, geometric mean productivity, stress tolerance index, yield index, and stress susceptibility index exhibited positive and significant correlations with grain yield under both N conditions; hence, either of these traits can be used to select low-N-tolerant genotypes. The common genotypes identified as LN-tolerant and responsive to N application in this study could be used as parental donors for developing N-efficient and responsive durum wheat varieties

Pathways to wheat self-sufficiency in Africa

A growing urban population and dietary changes increased wheat import bills in Africa to 9% per year. Though wheat production in the continent has been increasing over the past decades, to varying degrees depending on regions, this has not been commensurate with the rapidly increasing demand for wheat. Analyses of wheat yield gaps show that there is ample opportunity to increase wheat production in Africa through improved genetics and agronomic practices. Doing so would reduce import dependency and increase wheat self-sufficiency at national level in many African countries. In view of the uncertainties revealed by the global COVID-19 pandemic, extreme weather events, and world security issues, national policies in Africa should re-consider the value of self-sufficiency in production of staple food crops, specifically wheat. This is particularly so for areas where water-limited wheat yield gaps can be narrowed through intensification on existing cropland and judicious expansion of rainfed and irrigated wheat areas. Increasing the production of other sources of calories (and proteins) should also be considered to reduce dependency on wheat imports

Temperature, planting depth, and genotype effects on seedling characteristics and seeding rate effects on agronomic and quality performance of winter wheat (Triticum aestivum L.)

Temperature levels, planting depths, and cultivars, affected seedling traits as expected. An increase in temperature from 12.8/12.8 to 20/20°C increased coleoptile length by 21 min implying that higher temperatures facilitated coleoptile elongation. An increase in planting depth from 2.5 to 7.5 an increased coleoptile length, shoot length, and fresh weight and decreased root length and germination % of the seedlings across cultivars. Cultivars had a wide range of responses in their mean performance for the seedling traits. Scout 66, Nekota, and Niobrara were considered to have good seedling vigor while Alliance, Arapahoe and Centura, were considered to have poor seedling vigor. Strong and significant positive correlation between coleoptile length and germination %, shoot length and fresh weight, and fresh weight and dry weight were observed. In summary, planting depths and cultivars had a greater impact on seedling traits than did our temperature levels. Planting depth and cultivars are controllable management factors; hence the optimum depth must be practiced for the appropriate cultivar. Coleoptile length is the trait that was most significantly affected by temperature regimes, planting depths and cultivars. It is the best predictor of seedling vigor and hence can be used as a selection criterion in the development of cultivars with vigorous seedlings. While numerous experiments have studied how seeding rates affect agronomic performance of wheat (Triticum aestivum L.) cultivars, there are no or very few experiments which have studied how seeding rates affect end use quality particularly of modern wheat cultivars. Twenty winter wheat cultivars, were evaluated to assess the effect of cultivar and seeding rate on agronomic and quality performance of wheat. Significant differences among environments, seeding rates, cultivars and some of their interactions were identified. Lower seeding rates decreased stand density, grain yield and thousand-kernel weight and caused later flowering. Lower seeding rates also lowered flour yield and mixing time and raised flour protein content and mixing tolerance. Cultivars responded more to environmental conditions than to seeding rates. Agronomic and end use quality traits are greatly influenced by the prevailing environmental conditions, but not as much by seeding rates. Seeding rate is a predictable environmental factor which affects some agronomic and end use quality traits of wheat, hence should be carefully studied to obtain higher grain yields with relatively better end use quality

The CIMMYT wheat breeding strategies and its relevance to Ethiopia

Wheat is the most important food security crop globally. Recent world wheat production stand at 766 million tons on 216 million hectares though wheat production is challenged by various biotic, abiotic, and other factors. As a global leader in wheat research, CIMMYT’s primary goal is to develop broadly adapted germplasm with high and stable yield, durable disease resistance, stress tolerance and acceptable end-use quality strategically addressing the different mega-environments such as irrigated regions, high-rainfall areas, acid soils, semiarid zones, tropical areas, and winter wheat zones. CIMMYT’s Global wheat program is one of the most important public sources of high yielding, nutritious, disease resistant and climate-resilient wheat varieties for Africa, Asia, and Latin America. The program works with the International Center for Agriculture Research in the Dry Areas (ICARDA), the CGIAR Research Program on Wheat, and NARS. The CIMMYT wheat breeding program is supported by multidisciplinary team of experts with breeders strategically and internationally located at key regional offices to facilitate germplasm and information exchange as well as technically support NARS. The primary focus of the breeding program is on core (must have) traits with some emphasis on additional traits for specific environments. The center is crossing, selecting, developing, and distributing stable, and high yielding advanced lines which includes some Zn and Fe enriched germplasm, with durable pest resistance, stress tolerance and superior quality using the different strategies, and methods, highlighted. In addition, CIMMYT collaboration with Ethiopian NARS in some areas will also be briefed

Management of wheat rust diseases, challenges and the way forward

Wheat is the most important food security crop globally. Recent world wheat production stand at 766 million tons on 216 million hectares though wheat production is challenged by various biotic, abiotic, and other factors. As a global leader in wheat research, CIMMYT’s primary goal is to develop broadly adapted germplasm with high and stable yield, durable disease resistance, stress tolerance and acceptable end-use quality strategically addressing the different mega-environments such as irrigated regions, high-rainfall areas, acid soils, semiarid zones, tropical areas, and winter wheat zones. CIMMYT’s Global wheat program is one of the most important public sources of high yielding, nutritious, disease resistant and climate-resilient wheat varieties for Africa, Asia, and Latin America. The program works with the International Center for Agriculture Research in the Dry Areas (ICARDA), the CGIAR Research Program on Wheat, and NARS. The CIMMYT wheat breeding program is supported by multidisciplinary team of experts with breeders strategically and internationally located at key regional offices to facilitate germplasm and information exchange as well as technically support NARS. The primary focus of the breeding program is on core (must have) traits with some emphasis on additional traits for specific environments. The center is crossing, selecting, developing, and distributing stable, and high yielding advanced lines which includes some Zn and Fe enriched germplasm, with durable pest resistance, stress tolerance and superior quality using the different strategies, and methods, highlighted. In addition, CIMMYT collaboration with Ethiopian NARS in some areas will also be briefed

Virulence analysis of wheat stem rust (Puccinia graminis f. sp. tritici) in Horro Guduru Wollega, Western Ethiopia

Stem rust caused by Puccinia graminis f. sp. tritici is one of Ethiopia's most serious wheat diseases. Because of mutation and genetic recombination, stem rust can rapidly evolve new virulence to resistant genes. The Ethiopian highlands are well-known hotspots for the rapid emergence and spread of new wheat stem rust races. The objective of this study was to determine the virulence diversity and spatial distribution of Pgt races in the main wheat-growing districts, Horro Guduru Wollega. Wheat stem rust samples were collected from Abay Chomen, Amuru, Guduru, Hababo Guduru, Horro, Jardaga Jarte, Jimma Ganati and Jimma Rare districts during the main cropping seasons of 2015 and 2016. In the study, 147 stem rust isolates were derived from 121 viable samples. The physiological races of stem rust were determined on seedlings of standard wheat stem rust differentials using the International System of nomenclature. Twelve (12) physiological races of stem rust were identified. TKTTF, TTKSK, JRCQC, TRTTF and TTTTF were the most common in all districts with a frequency of 53.1%, 15.6%, 14.3%, 6.8% and 2.7%, respectively. TKTTF and TTKSK, two highly virulent races, were found in all districts. Four stem rust resistance genes (Sr11, Sr31, Sr36 and SrTmp) confer resistance to the majority of the virulent races identified. Sr24 was effective against all virulent races in this study but ineffective against the Ug99 variant (race TTKTT) detected in the country. The findings could be helpful for breeders to select many effective resistance gene combinations to provide more durable stem rust resistance

Smallholders' coping mechanisms with wheat rust epidemics: Lessons from Ethiopia.

Crops are variously susceptible to biotic stresses-something expected to increase under climate change. In the case of staple crops, this potentially undermines household and national food security. We examine recent wheat rust epidemics and smallholders' coping mechanisms in Ethiopia as a case study. Wheat is a major food crop in Ethiopia widely grown by smallholders. In 2010/11 a yellow rust epidemic affected over one-third of the national wheat area. Two waves of nationally representative household level panel data collected for the preceding wheat season (2009/10) and three years after (2013/14) the occurrence of the epidemic allow us to analyze the different coping mechanisms farmers used in response. Apart from using fungicides as ex-post coping mechanism, increasing wheat area under yellow rust resistant varieties, increasing diversity of wheat varieties grown, or a combination of these strategies were the main ex-ante coping mechanisms farmers had taken in reducing the potential effects of rust re-occurrence. Large-scale dis-adoption of highly susceptible varieties and replacement with new, rust resistant varieties was observed subsequent to the 2010/11 epidemic. Multinomial logistic regression models were used to identify the key factors associated with smallholder ex-ante coping strategies. Household characteristics, level of specialization in wheat and access to improved wheat seed were the major factors that explained observed choices. There was 29-41% yield advantage in increasing wheat area to the new, resistant varieties even under normal seasons with minimum rust occurrence in the field. Continuous varietal development in responding to emerging new rust races and supporting the deployment of newly released resistant varieties could help smallholders in dealing with rust challenges and maintaining improved yields in the rust-prone environments of Ethiopia. Given the global importance of both wheat and yellow rust and climate change dynamics study findings have relevance to other regions