This work was carried out to study the response of five bread and two durum wheat cultivars to stem rust and its effect on grain yield under field conditions at Sids and Beni Sweif stations during the three growing seasons 2011/2012, 2012/2013 and 2013/2014. The loss in grain yield and kernel weight of the different wheat genotypes was variable according to the varietal response. Grain yield and kernel weight of the protected plots (protected by the effective fungicide Sumi-eight 5EC(CE)-1-(2,4-dichlorophenyl)1-4,4-dimethyl1-2-(1,2,4-triazol-y1)Pent -1-en -3-0L) at the rate of 70cm /200litter water per Fadden ) of all wheat genotypes were higher than the infected ones. Significant differences were found between infected and protected wheat genotypes.. Disease severity was recorded weekly to estimate area under disease progress curve (AUDPC). The AUDPC ranged from 85.33 to 405.00 (Sids 1 and Sohag 3) during 2011/2012, from 181.66 to 805.00 (Shandwel 1 and Sohag 3) during 2012/2013, and from 142.33 to 585.00 (Shandwel 1 and Sohag 3) during 2013/2014. Losses in kernel weight ranged from 3.39% to 31.03% (Sids 1 and Misr 1) during 2011/2012, from 9.79% to 44.18% (Sids 1 and Sohag 3) during 2012/2013,and from 5.67% to 26.86% (Sids 1 and Sohag 3) during 2013/2014. Yield losses ranged from 5.70% to 37.52% (Shandwel 1 and Misr 1) during 2011/2012, from 7.75% to 45.78% (Shandwel 1 and Misr 1) during 2012/2013, and from 7.14% to 30.59% (Sids 1 and Sohag 3) during 2013/2014. Yield losses correlated strongly with AUDPC. The results of this study indicate that bread wheat cultivars are (Giza 168,Sakha 93, Sids 1, Misr 1, Misr 2 and Shandwel 1) and Durum wheat are ( Beni Sweif 5 and Sohag 3) more tolerant than durum wheat cultivars. The Egyptian bread wheat cultivars Sids 1 and Shandawel 1 are more tolerant than the other bread wheat cultivars.
Primary Author: Abd El Badia, Wheat Disease Research Department
Food crisis is a major concern in Egypt, where drought and saline soils are ubiquitous. Wheat is a staple food in Egypt, which is only moderately tolerant to drought and salinity. Due to its rapidly increasing demand, there is an urgent need in Egypt to enhance wheat yields under drought and salinity conditions. Improving salinity or/and drought tolerance of genotypes is inhibited by a lack of efficient evaluation methods. High throughput precision phenotyping provides an innovative technology to screen for enhanced salt or drought tolerance from a large of number of genotypes under field conditions and can have immediate value to plant breeding. Therefore, we have tested several wheat phenotyping techniques i.e., canopy temperature (CT), spectral reflectance (SR), chlorophyll content (SPAD value), crop ground cover, relative water content (RWC), Water soluble carbohydrates (WSC), leaf area index (LAI), crop morphological traits, and grain wheat yield and yield components. We documented strong correlation/linear regression/polynomial regression between the wheat phenotyping techniques and in-season biomass/grain yield. It could be concluded that the documented results confirmed that several landraces were selected as drought/salinity tolerant out of 762 wheat landraces wheat were screened. Using high throughput precision phenotyping could provide an innovative technology and can have immediate value to plant breeding.
Primary Author: Abdelhamid, National Research Centre
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.
Primary Author: Abera, Ethiopian institute of agricultural research
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.
Leaf rust is the most common rust in wheat production areas of Syria and causes significant annual yield losses. Using genotypes with durable resistance is the most economical way of controlling the disease. One of the best-known leaf rust resistance genes is Lr46 that confers a slow rusting type of adult plant resistance. The main objective of this study was to identify Lr46 in durum wheat genotypes using morphological and molecular markers. Thirty-two durum wheat genotypes were evaluated for response to leaf rust at the seedling and adult plant stages. Twelve genotypes (37.5%) were resistant (R), 10 (31.25%) were moderately resistant (MR), seven (21.87%) were moderately susceptible (MS), and three (9.37%) were susceptible (S). Molecular marker analyses using SSR marker wmc44 showed that 16 genotypes (50%) carried Lr46/Yr29. The genotypes possessing the marker linked to Lr46/Yr29 could be used for selection of Lr46/Yr29 in breeding for slow rusting resistance in durum.
Improvement of wheat (Triticum aestivum L.) is a major goal of plant breeders and pathologists to ensure food security and self sufficiency. Relationship between different levels of stem, stripe and leaf rust severity on the two grain yield components (1000-kernel weight and plot yield) were studied during 2015/2016 and 2016/2017 seasons at Sids Agricultural Research Station. Different epiphytotic levels of stem, stripe and leaf rust were created using spreader artificial inoculation and spraying the fungicide Sumi-eight. To create different rust severity, one, two, and three sprays were applied at 7 day intervals. Protected control treatment was obtained by spraying the fungicide four times. Correlation coefficient (R<sup>2</sup>) analysis depicted that positive correlation was found between different rust severity levels and yield loss. In 2015/2016 growing season, which stem rust started early, disease severity (%) reached its relatively high percentage (80%) with the highest loss (%) in both 1000 kernel weight (36.3%) and plot weight (37.82%). The effect of stripe rust infection on yield components was lower than those of stem rust and lowest in leaf rust. On the other hand, the lowest loss was observed with 10% of stem, stripe and leaf rust which sprayed three times. During 2016/2017 stripe rust infection caused the highest loss (%) in yield components, under the highest level 80% of severity, on the other hand leaf rust showed low level of loss (%) Compared with the stripe and stem rust.
Primary Author: Abou-Zeid, Wheat Diseases Department Plant Pathology research Institute, Agriculture Research Center.
Wild species are sources and donors of many valuable traits for wheat improvement. We studied winter wheat introgression lines for productivity traits, disease resistance, and protein, globulin, gliadin and glutenin contents as well as grain mineral concentrations. Laboratory and field studies allowed selection in populations segregating for resistance to yellow rust and leaf rust. Lines 1718, 1721-9, 1721-4, 1675 and 1727 had the highest yields (6.2 t/ha) and stable leaf rust and stem rust resistances, but were still variable in response to stripe rust (30-80 S). Lines 1718 (Bezostaya 1 x Ae. cylindrica, genomes CCDD) and 1721 (Bezostaya 1 x T. militinae2 - 6, ABG) were resistant to stripe rust in trials at yield levels of 3.7-7.6 t/ha and from 5.7 to 8.2 t/ha, respectively. Line 1675 (Zhetisu x T. kiharae, ABGD) was resistant to all three rusts. Line 1676 (Steklovidnaya 24 x T. timopheevi, ABG) was resistant to LR and SR at a yield level of 8.3 t/ha, and 1671 (Zhetisu x T. militinae, ABG) was resistant to YR and SR at a yield level of 7.5 t/ha. Protein contents of the lines ranged from 13.6 to 18.4%, and grain mineral contents were above average.
Primary Author: Abugaliyeva, Kazakh Research Institute of Agriculture and Plant Growing
Leaf rust (LR), caused by Puccinia triticina, is among the most important diseases of wheat (Triticum aestivum L.) crops globally. The most sustainable method for controlling rust pathogens is deployment of cultivars incorporating durable forms of resistance, such as adult plant resistance (APR). However, phenotyping breeding populations or germplasm collections for LR resistance in the field is dependent on weather conditions and limited to only once a year. In this study, we report a protocol for phenotyping APR to LR incorporating ‘speed breeding’ technology, which utilizes controlled temperature regimes and 24-hour light to provide accelerated growth conditions (AGC) – enabling up to 6 plant generations of wheat per year. A panel of 22 genotypes, including disease standards carrying known APR genes along with a diversity panel comprising 300 accessions (including winter types and landraces) were characterized for resistance to LR under AGC and in the field. Analysis of genotypes displaying APR revealed that disease response expressed on flag–2 leaves under AGC was highly correlated with field-based measures (R2 = 0.76). Analysis of the diversity panel indicated that APR was expressed by plants that had obtained the stem elongation stage (i.e. GS≥30) prior to inoculation. Despite the high degree of genetic diversity in the panel, strong correlations between LR response under AGC and the field were observed, and were further improved when field response was adjusted based on growth stage (R2 = 0.81). The diversity panel was also screened with DNA markers for known APR genes (Lr34, Lr46 and Lr67), which identified 22 accessions carrying potentially novel sources. This method integrates assessment at both seedling and adult growth stages and requires only seven weeks to complete, enabling up to seven consecutive assays annually. When coupled with ‘speed breeding’, this approach could also accelerate introgression of resistance genes into adapted wheat cultivars.
Primary Author: Adnan Riaz, The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Australia
Accelerated climate change affects components of complex biological interactions differentially, often causing changes that are difficult to predict. Crop yield and quality are affected by climate change directly, and indirectly, through diseases that themselves will change but remain important. These effects are difficult to dissect and model as their mechanistic bases are generally poorly understood. Nevertheless, a combination of integrated modelling from different disciplines and multi-factorial experimentation will advance our understanding and prioritisation of the challenges. Food security brings in additional socio-economic, geographical and political factors. Enhancing resilience to the effects of climate change is important for all these systems and functional diversity is one of the most effective targets for improved sustainability.
Primary Author: Adrian Newton, Scottish Crop Research Institute (SCRI), U.K.
Stem (black) rust is a potentially important disease in northern, western and southern Iran. A new Pgt race with virulence to gene Sr31 appeared in Iran in 2007. Similar races have spread in Africa and some CWANA countries. In 2014 stem rust was widespread in western, northern, northwestern and central Iran, but at low severities. Thirty-nine stem rust samples were collected for race analysis. After purification and increase each isolate was inoculated to a set of 20 North American differentials in the greenhouse. Infection types were recorded 12-14 days after inoculation using the scale described by McIntosh et al. (1995, Wheat Rusts: An Atlas of Resistance Genes, CSIRO, East Melbourne, Australia). Races TKSTC (59%), TKTTC (20%), TTTTC, KTTSK (virulent on plants with Sr31), TTSTC, PTTTF and TTTTF were detected. Race TKSTC was common in western, northwestern and central Iran. Except for avirulence to Sr17 this race is similar to the race (TKTT) that caused a stem rust epidemic in Ethiopia in 2013.
Primary Author: Afshari, Seed and Plant Improvement Institute (SPII), Iran