Ethiopian institute of agricultural research
Dr. Netsanet B. Heyi, Dr. Getaneh W. Wolderufael, Tsegab T.
Stem rust caused by Puccinia graminis f. sp. tritici (Pgt) is a major production constraint in most wheat growing areas of Ethiopia. The stem rust pathogen is capable of rapidly developing new virulence to resistance genes. The highlands of Ethiopia are considered a hot spot for Pgt diversity. The present study was conducted to investigate the virulence diversity and spatial distribution of races of Pgt in the major wheat growing areas of Ethiopia. The physiologic races of Pgt were determined on seedlings of the standard wheat stem rust differentials following the international system of nomenclature. Stem rust race analyses were carried out both at Ambo Plant Protection Center and the Cereal Disease Laboratory in Minnesota. 426 stem rust samples were collected from major wheat growing of the country in the 2016 cropping season and 185 viable samples were analyzed. Stem rust races TKTTF, TTKSK, TTTTF, JRCQC and RRTTF were identified. Among the identified races, TKTTTF was dominant at a frequency of 78.7% followed by TTKSK (10.6%). Race TTTTF was found for the first time in Ethiopia in 2016. Only one resistance gene in the differential set, Sr24, was effective against all isolates. Stem rust resistance gene Sr31 was found to confer resistance to most of the races prevalent in Ethiopia with the exception of Ug99. Sr24 could be used in combination with other resistance genes in breeding for resistance to stem rust in Ethiopia.
University of Delhi South Campus, New Delhi
Towards understanding the molecular mechanisms of heat stress tolerance, we have analyzed heat stressed substractive cDNA libraries and undertaken genome-wide transcriptome exploration for genes associated with spike photosynthetic efficiency during thermal stress. The photosynthetic efficiencies of Aegilops tauschii and Ae. speltoides were also compared. While the former displayed nearly complete recovery of PSII, the adverse effect was more pronounced in the latter. Functional characterization of heat stress-associated transcription factors and thermal stress-associated proteins was also undertaken e.g. TaHSF, TabZIP, TaZnF and TaMIPS, and TaLTPs in the Indian wheat germplasm. Functional characterization of the three heat stress transcription factors was upregulated under high temperatures and other abiotic stresses. They also showed early flowering and better performance with respect to their growth and yield after heat stress. Additionally, we have identified various interacting components associated with thermal stress-mediated plant signaling partners during thermal stress.
AgriLife Research, Texas A&M University
Monsanto, through the MBBIScholars Program, has invested $13 million over an 8 year period for training rice and wheat breeders from around the World. The Judging Panel for MBBISP selected 89 Scholars from 432 applicants. The selected scholars were from 30 different countries. Scholars selected included 35 young ladies and 54 young men, 37 are in rice breeding and 52 in wheat breeding. Currently 28 Scholars are still completing their PhD programs (As of 8/8/2017). This past year Monsanto established the "Ted Crosbie Monsanto Beachell-Borlaug International Scholars Impact Award" to begin recognizing Scholar contributions. To be eligible for the "Ted Crosbie MBBIScholars Impact Award," scholars must have received their PhD and must apply for the award. Bhoja Basnet, selected as an MBBIScholar in 2009 who is now in charge of CIMMYT's Hybrid Wheat Breeding program, was selected to receive the "Ted Crosbie Monsanto Beachell-Borlaug Scholars Program Impact Award" this year. Scholar contributions are in wheat and rice breeding as well as in other crops. Hopefully the Ted Crosbie MBBIScholars Impact Award will continue to recognize accomplishments of Scholars into the future. MBBIScholars are making an impact and we look forward to recognize their career contributions. Employment of Scholars post PhD will be reviewed.
P. triticina has a biotrophic relationship with wheat and needs certain elements from the wheat host for a successful life cycle. In recent years, several long lasting, minor resistance genes have been cloned, and their function suggests that the resistance is not due to a classic NB-LRR gene, but a gene that functions in a biotrophic pathway. The hypothesis was proposed that modification of a susceptibility gene can provide broad, long lasting resistance. To test this hypothesis, Thatcher was treated with EMS and screened for changes in susceptibility. M5 lines were evaluated in the greenhouse with BBBD Race 1 and 5 lines were identified. Also, M5 lines were planted in the field to verify the resistance and test the resistance effectiveness to natural infections of P. triticina. The same five lines were resistant in the field. Resistance ranged from few pustules, a race specific-like reaction, lesion mimics with few or no pustules, and near immunity. These lines were backcrossed to Thatcher, and resistant F2 plants were bulked and sequenced. Gene candidates will be identified and discussed.
Mohamed 5 university/ICARDA
Amadou tidiane sall, meryem zaim, Ayed Al-abdallat, Gregor Gorjanc, Jesse Poland, Miloudi Nachit, Abdel karim Filali Maltouf, Bouchra Belkadi, Rodomiro Ortiz, Filippo Bassi
Durum wheat production is globally important, but grain yield has been stagnating in recent decades. In order to ensure that its production maintains the pace with increasing demand, breeding for high grain yield must be supported by molecular-based methods. Genomic estimated breeding values for selection and genome scan were assessed as molecular tools holding maximum potential for durum wheat breeding. Four recombinant inbred line populations bred by inter-mating elite were sown in yield trials at five sites. All progenies were characterized using "genotyping by sequencing" method. A consensus map was developed, and missing genotypes were imputed using a Hidden Markov model to reach a total of 1987 polymorphic markers. Models accounting for genotype environment interactions were used to estimate the genetic component of each measured trait. Hence, Bayesian ridge regression was used to determine the predicted values and their relative accuracy in several combinations, testing full-sibs and half-sibs as training population for grain yield and 1,000 kernel weight. The high level of accuracy achieved suggests that GEBV for selection holds great potential for durum wheat breeding, as long as full-sibs are used as training populations, in combination with statistical models that account for G?E. In order to test the exploitability of genome scan to guide breeding crosses, a separate genome-wide association study was conducted. 288 elite were sown in the south of Morocco and at two sites along the Senegal River for two years. These sites show a temperature differential of 10?C. Implementing a GE model facilitated identifying the most heat tolerant among the tested entries. 8,173 polymorphic SNPs were inquired, and several associations could be identified between markers and the ability to withstand the heat gradient. Hence, GWAS holds great potential to increase genetic gain in breeding via increased accuracy in determining the crosses to be made.
National Agronomic Institute of Tunisia
Sana Kamel, Elhem, Elfahem, Wissal Feriani, Hanen Sbei
In order to identify sources of resistance to tan spot caused by Pyrenophora tritici-repentis, 359 local wheat accessions were evaluated for reaction to the Oued-Mliz isolate in controlled conditions and in the field. Two and three assessments were carried out at the seedling and adult stages, respectively. There was a highly significant accession effect and 4.2% of accessions were highly resistant in both controlled conditions and the field. Assessments at the seedling stage were positively correlated with each other, and assessments in the adult stage were also positively correlated. However, assessments at the seedling stage were negatively correlated with those at the adult stage. One hundred and fifty five accessions with known origins (from 15 localities belonging to four districts) were projected on a graph defined by the two axes: reactions at the seedling stage and reactions at the adult stage. After placing the average reactions at the seedling and adult stages on the graph, four groups of accessions were obtained: accessions that were resistant to both stages, accessions that were resistant at the adult stage only, accessions that were resistant at the seedling stage only, and accessions that were susceptible at both stages. All four groups were found in each district. However, considering localities, reactions of accessions were highly variable. For example, accessions originating from Menzel Hbib were genetically variable and were represented in each of the four groups, whereas accessions from Sidi El Hani were all resistant at both stages. Further work is needed to study the genetic variability within and between localities and to better understand the resistant accessions.
Sathguru Management Consultants
Kanan Vijayaraghavan, Venugopal Chintada, Rituparna Majumder, Richa Kapur, K. Aishwariya Varadan
South Asia has the highest "wheat dependent" low income community in the world. Stem rust and blast are recognized as the most damaging disease of wheat in the region producing 19% of the world's wheat. In order to combat the potential threat the national research centers were geared up to track the real time movement of wheat diseases, generate disease incidence data and create an enabling environment to boost wheat research in the region through streamlined efforts and enhanced SAARC tool box deployed six years ago.
Recent data (2016-17) from the tool box has shown a significant increase in the data records captured in this region compared to previous years. This has been possible because of heightened awareness amongst the scientists and with the continuous capacity building through pre-season and in-season surveillance trainings organized by Sathguru in collaboration with National Wheat Research Institutes at various levels.
The model is helping partner institutes to be self-sufficient for generating, maintaining wheat disease surveillance data in national and global databases and exchanging real time information with stakeholders. The application have been widely deployed and competently being used by 95% of rust surveillance teams in the wheat fields of SAARC region.
The study will focus on how national research center's judicious decision of carrying out diligent surveillance during the season contributed to safeguarding wheat crops in their respective nations through increased vigilance on emergence of new races and targeted introduction of regionally resistant varieties. Further using this data scientist's can aim to strategize their wheat research for identification of resistant varieties and eventually resulting in increased productivity addressing food security of the region.
All Russian Research Institute of Biological Plant Protection
Irina Petrovna Matveeva
Yellow rust caused by Puccinia striiformis West. is a harmful and dangerous disease in the south of Russia. Yield losses under optimum conditions on highly susceptible varieties can vary from 10 to 100%. During the growing season of 2017, cool weather with constant precipitation from the third decade of April to the first decade of June contributed to the intensive development of the pathogen. Surveys of the main winter wheat production areas in five agroclimatic zones of the region revealed that yellow rust was prevalent in all areas. The maximum development of P.striiformis was observed in southern submontane and western Priazovsky agroclimatic zones. Some varieties such as Grom, Yuka, Tanya, Anka had losses to yellow rust of up to 30-40 %. In the central and northern agroclimatic zones, the losses averaged 5%, whereas in the dry eastern steppe zone losses were only up to 1%. The build up of yellow rust inoculum in the region raises concerns that in 2018, under favorable weather conditions in spring, winter wheat crops could be infected with the disease, especially in the wetter agroclimatic zones.
Ayele Badebo, Abebe Atilaw, Habtemariam Zegeye, Zerihun Tadesse, Wasihun Legesse, Terefe Fitta, Dawit Asnake
In Ethiopia, quality seed of improved varieties is the least expensive and most critical input for the sustainable production of wheat, a strategic food security crop grown by some 4.7 million households on 1.7 million hectares. Because wheat is self-pollinated, farmers can save and replant seed from their harvests for several years, without the variety losing its genetic identity. At the same time, recommended seed rates for wheat (150 to 200 kilograms per hectare) are significantly higher than those for tef (15 kg/ha) or maize (25 kg/ha), so some 255,000 tons of seed is required to sow Ethiopia's entire wheat area each year. Most of this still comes from informal seed systems; only four seed enterprises (ESE, ASE, OSE and SNNPSE) currently produce certified seed of various crops and they lack the capacity to supply enough high quality seed for the nation's approximately 20 million households. In collaboration with the Ethiopian Institute of Agricultural Research (EIAR) and through the USAID-funded project "Seed multiplication and delivery of high-yielding rust resistant bread and durum wheat varieties to Ethiopian farmers," the International Maize and Wheat Improvement Center (CIMMYT) is working to increase wheat farmers access to affordable, certified seed of improved varieties that are high-yielding and also feature durable resistance to the rust diseases. Approaches pursued include the fast-track evaluation and release of improved varieties, the pre-release or accelerated seed multiplication of released wheat varieties through formal and informal seed systems, and demonstrations and scaling up of improved wheat varieties. This paper describes best practices to address seed shortages faced by wheat farmers in 53 woredas.
Institute of Evolution and the Department of Evolutionary and Environmental Biology, University of Haifa, Israel
Dina Raats, Lin Huang, Valeria Bocharova, Jorge Dubcovsky, Abraham Korol, Tzion Fahima
Wild emmer wheat (Triticum dicoccoides, (DIC)) is an important source of resistance to stripe rust due to presence of Puccinia striiformis in its natural habitats with high humidity and relatively low temperatures that are favorable for stripe rust development. Previously, we showed that DIC accessions from northern Israel were highly resistant to stripe rust. According to the rust responses of three DIC accessions (G25, H52, G303) and mapping of the resistance to relatively close, but different, genetic positions on chromosome 1BS, three different resistance genes were assumed to be present. However, the development of additional critical recombinants and new higher resolution genetic maps for these three genes in subsequent work led us to place YrH52 and YrG303 in the same genetic interval as Yr15, suggesting that the three putative genes are allelic or identical. The recent cloning of Yr15 allowed us to test this hypothesis using an EMS mutagenesis approach. We sequenced the Yr15 locus in five yrH52 and three yrG303 susceptible mutants and identified missense point mutations associated with the susceptible phenotype in each one. Thus, YrH52 and YrG303 may not be new genes. Further work is under way to determine if these genes are allelic or identical.