The University of Jordan
Ayed Al Abdallat, Monther Tahat
Studies on whet stem rust (WSR) in Jordan are considered to be old. There was only one study conducted in the late 1980's by Abu-Blan and Duwayri (1989) to evaluate the infection of wheat cultivars with black stem rust disease (Puccinia graminis f. sp. tritici). Recently, reports of stem rust were published in Israel and Lebanon in 2010 and first report of Ug99 was reported in Egypt in 2014. The objectives of our research are to: (i) survey wheat growing areas for WSR in Jordan during the years 2017-2020, (ii) identification of WSR races isolated from Jordan morphologically and molecularly, (iii) analyze rust populations in terms of their response to known differential sets, pathotype distribution and diversity, (iv) screening the response of Jordanian wheat germplasm to the identified WSR strains, and (vi) study the population diversity of WSR races using RT-PCR and SNP genotyping. In 2017 a total of 270 fields of wheat and barley in the wheat and barley growing areas in Jordan were surveyed from March-May. The survey covered northern, middle, and southern parts of Jordan (arid and semi-arid regions). Altitude, longitude, and latitude data was recorded. Only few WSR pustules (n=4) were collected because the environmental conditions were not suitable for the disease to develop. On the other hand, wheat stripe rust was very common in the wheat growing areas mainly at the southern parts of the country. Other fungal plant pathogens were also reported including smuts, spots, blotches, powdery mildew, crown rot, fusarium head blight, and flag smut.
Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-University of Bonn
Mohammad Wali,Salari, Kobra, Yusefi, Mohammad, Yusefi, Gul Mohammad, Ajir, Wakil Ahmad, Sarhadi, Jens, L?on, , , , , , , , , , , , , , , , , ,
Bread wheat is a staple food in Afghanistan. Breeding for improving yield and its components in Afghan bread wheat without using new molecular methods such as marker-assisted selection (MAS) and quantitative trait loci (QTL) mapping approaches is difficult. Therefore study of genetic analysis by focus on yield and its components as first steps is necessary. Genetic analyses were performed on a winter wheat core collection of 20 accessions and commercial varieties sampled from different regions of Afghanistan and twenty agronomic traits were evaluated over three years under fully irrigated, rain-fed and drought treatments. Grain yield was the most important trait to water deficit and was highly correlated with other agronomic traits. The germplasm was structured into two sub-populations. Field plots of the genotypes were treated to one of three treatments including full irrigation, rain supplied and rain-sheltered. A randomized complete block design with three replicate was used every year of the trial. For every agronomic trait, variance components, heritability (h2) and genetic correlations was calculated. Results of the study showed that these genotypes may be good source for national breeding programs. The multiple statistical in this study showed that results of genetics correlation and regression analysis are same. Further analysis of these traits with additional experimental data to attain persuasive conclusion is suggested.
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, P. R. China
Qilin,Wang, Jianhui, Wu, Qingdong, Zeng, Lili, Huang, Dejun, Han, Zhensheng, Kang, , , , , , , , , , , , , , , , , ,
The combination of several additive, partial resistance genes has been proposed as a preferred strategy to breed wheat cultivars with acceptable levels of durable resistance. The German winter wheat cv. Centrum has displayed high levels of adult plant stripe rust resistance (APR) in field environments for many years. One hundred and fifty one F2:7 RILs were developed from a cross between susceptible landrace Mingxian169 and Centrum to determine the inheritance of the APR resistance. The RILs and parents were evaluated for maximum disease severity (MDS) in the field during the 2015-2016 and 2016-2017 cropping seasons. Affymetrix 35K single nucleotide polymorphism (SNP) arrays were used to genotype the RILs and parents. In addition, the 660K SNP array was used to genotype bulked extreme pools and parents for saturation mapping. Four stable QTL were detected in all tested environments using inclusive composite interval mapping (ICIM); namely QYrCEN.nwafu-4AL, QYrCEN.nwafu-4BS, QYrCEN.nwafu-7BL, and QYrCEN.nwafu-7DS. QYrCEN.nwafu-4BS and QYrCEN.nwafu-7DS were contributed by MX169, QYrCEN.nwafu-4AL and QYr-CEN.nwafu-7BL were contributed by Centrum. QYrCEN.nwafu-7BL and QYrCEN.nwafu-4AL appear to represent new APR loci based on map comparisons. QYrCEN.nwafu-4BS contributed by MX169 also seems to represent a new locus. QYrCEN.nwafu-7DS is likely Yr18. Although MX169 was fully susceptible in our nurseries it is positive for the widely used marker csLV34. Reference lines carrying Yr18 are moderately resistant. Our hypothesis is that MX169 probably carries the inhibitor reported in Chinese landrace varieties by Wu et al. (2015, Plant Breeding 134: 634-640). SNP markers within these QTL were converted to KASP markers and validated in a subset of 120 diverse lines. These KASP markers should be useful for marker-assisted selection to improve stripe rust resistance in breeding programs.
The University of Agriculture, Peshawar, Pakistan
Muhammad Khan, Aamir Iqbal, Sher Nawab, Sohail Ahmed, Muhammad Imtiaz, Sajid Ali
Resistance breeding for wheat leaf rust requires testing of breeding materials under field conditions, which must be complemented with diagnostic molecular makers. A set of 28 exotic wheat lines from advanced CIMMYT material along with three check varieties (Siran, Atta-Habib, Ghanimat-e-IBGE) were tested at three contrasting locations (Peshawar, Mansehra and Lakki-Marwat) and were genotyped with markers linked to three Lr genes (LrPr, Lr37, and Lr34). The overall leaf rust pressure was low during the wheat season of 2015-16, with the maximum disease observed at Lakki-Marwat (up to 70%), followed by Peshawar (up to 50%) and the minimum disease at Mansehra (up to 30%). Despite the overall low leaf rust pressure, the germplasm behaved variably in terms of leaf rust resistance as revealed through average co-efficient of infection (ACI). According to ACI value, 16 out of 28 genotypes were completely resistant, while few genotypes showed partial resistance. The maximum CI value was recorded for wheat line W-SA-87, which was 55 at Lakki Marwat, 33 at Peshawar and 15 at Mansehra, while 18 lines had CI value of zero across the three locations. Variability existed in yield parameters with W-SA-84, W-SA-78 and W-SA-79 producing the better grain yield. Genotyping with Lr linked markers viz., STS-7 (LrPr), SC-Y15 (linked with Lr37) and csLV34 (linked with Lr34) revealed that among the tested lines LrPr was the most frequent (83.8%), present in 26 lines; followed by Lr37 (77.4%), present in 24 lines, while Lr34 was present in 16 lines (71.1%). All three genes were detected in 45% of the germplasm. Cluster analysis grouped the germplasm in four clusters based on both phenotypic and molecular markers data. The information generated in the present study would be valuable in resistance breeding for a better control of leaf rust disease in Pakistan.
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.
Department of BioEngineering, Birla Institute of Technology, Mesra, Ranchi, India
Manish Kumar, Kunal Mukhopadhyay
Bread wheat (Triticum aestivum L.) being the world's most popular edible cereal, plays a major role in global economy. Rust in wheat leaves, caused by Puccinia triticina, affects grain quality and severely retards its production worldwide. Micro(mi)RNAs are considered major components of gene silencing and so have a great role to play during stress. The present study focuses on identification of miRNAs, produced by host to suppress pathogen as well as delivered by pathogens to encounter host defence mechanism. Therefore, these miRNAs may be called as leaf rust responsive microRNAs. Small RNA and degradome libraries were prepared from a pair of near isogenic lines of wheat (HD2329, HD2329+Lr24), one set was mock inoculated while the other set was inoculated with urediniospores of leaf rust pathogen. Using these libraries as input a vast number of miRNAs rather a population of miRNAs were identified derived from wheat that were targeting genes mostly involved in functions like defense response, signal transduction, development, metabolism, and transcriptional regulation.
When reads specifically produced under pathogen inoculation were taken as input with Puccinia triticina genome sequences as reference, only three putative miRNA precursor loci were detected and the molecules produced were called miRNA-like molecules as their precursors lacked one or two criteria essential for a true miRNA precursor. The identified miRNAs were targeting genes like F-box protein, MAP kinase, calmodulin and susceptible antioxidant protein. We further identified the presence of argonaute and dicer like domains in Puccinia proteome available at FungiEnsembl which strengthens presence of RNAi-like activities in Puccinia.
In addition, differential expression of wheat as well as Puccinia small RNAs using stem loop RT-PCR under varying time points of disease progression (0-168 hpi) revealed their direct connection with stress responses.
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.
The University of Agriculture, Peshawar, Pakistan
Muhammad,Khan, Safi, Kathi, Zahoor, Swati, Manzoor, Hussain, Annemarie, Justesen, Muhamamd, Imtiaz, , , , , , , , , , , , , , , , , ,
Considering the importance of wheat rust diseases in Pakistan and the recent identification of yellow rust pathogen (Puccinia striiformis f. sp. tritici) centre of diversity in Pakistan, the present study was designed to assess the status of three wheat rusts across the country during 2015-16 and 2016-17 and analyze the population structure of P. striiformis f. sp. tritici . A total of 451 fields (from 68 districts) were surveyed during 2016 and 480 fields (from 69 districts) during 2017. A high yellow rust pressure was present during 2016 throughout Pakistan, while it was predominant only in the Northern half during 2017. Leaf rust was present in the central part of the country, while stem rust was only found in the south. In Sindh province (located in the south), yellow rust was reported unexpectedly with high severity (>60%) on varieties like Kiran and Galaxy during both the years. A set of 513 samples of P. striiformis were genotyped with microsatellite markers to assess the population diversity and spatial structure. and infer on the cause of epidemics in the Sindh province. Population genetics analyses confirmed a recombinant population structure across all locations except the Sindh province, where relatively lower diversity and lack of recombination signature was revealed. At least five genetic groups were identified in the overall population, which were found across all locations, except Sindh province where one of the genetic groups was predominant. The P. striiformis population from Sindh province with low diversity that caused unexpected epidemics in a relatively warmer region needs to be further investigated for specific adaptation traits. Our results confirmed the high diversity across Pakistan, which lies in the Himalayan centre of diversity of the pathogen. This high diversity was present in locations without the presence of alternate host (Berberis spp.) and could potentially be associated with regular migrants from the Berberis zone into the whole country.
Crop and Horticultural Science Research Department, Ardabil Agricultural and Natural Resources Research and Education Center, Ag
Yellow (stripe) rust caused by Puccinia striiformis f. sp. tritici is the most devastating disease of bread wheat (Triticum aestivum) in the world. A wide range of virulent yellow rust pathotypes is evolving in different regions of the world causing the breakdown of widely utilized sources of resistance in wheat. Hence, the knowledge of virulence factors of pathogen and determining of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programs. During cropping seasons of 2015-2016 and 2016-2017, virulence of the wheat yellow rust was investigated by planting differential cultivars and isogenic lines in a yellow rust trap nursery in Ardabil, northwest of Iran . Results showed stripe rust infections on some cultivars carrying Yr genes such as Yr1, Yr3, and Yrsp previously known to be resistant. The virulence spectrum of race population in Ardabil was identical to the Warrior race or its variants which is different from characterized races in Ardabil by carrying virulence combination for Yr1, Yr3, Yr17, Yr32, and YrSP and is avirulent on Yr8 and Yr27. Except for Yr8, Yr17 and Yr27, the common races in Ardabil are generally avirulent on Yr1, Yr3, and YrSP. This is the first report of race population in Ardabil (Iran) which is similar to the Warrior race or its variants.
Food and Agriculture Organization of the UN
Munira Otambekova, Bahromiddin Husenov, Alexei Morgounov
Wheat as a staple food crop in Tajikistan plays a crucial role for food security of population. However its production is threatened by number of limiting factors, and among them wheat rusts are most devastating disease.
Close collaboration of local scientists and breeders was established with International Agricultural Research Centers, including CIMMYT and ICARDA since early 2000. In the result, a number of high yielding and rust resistant varieties were released in Tajikistan that occupy presently about 40% of total wheat area.
Among the major breeding objectives selection of varieties with high resistance to wheat rusts, especially yellow rust considered as a priority task. The following new varieties originated from CIMMYT international nurseries were released in the country in past years, which bear high resistance to yellow rust: Sarvar (CHEN\AEGILOPS SQUARROSA (TAUS0//BCN/3/BAV92), Yusufi (SOROCA), Vahdat (VORONA SN079), Isfara (SW89.5181/KAUZ), Fayzbaksh (TAM200.KAUZ) and Shokiri (SHARK/F4105W2.1).
During the last three years eight new varieties were submitted for official testing, and two of them already are released in 2017 (Murodi and Durakhshon) and remaining ones are under official testing. The varieties and their origin are followings: Murodi (CHEN/AE.SQ//WEAVER/3/SSERI1), Durakhshon (ATTILA/3*BCN*2//BAV92), Kamol (PYN/BAU//LAGOS-19/3/ID800994.W/VEE), Zarnisor (CROC_1/AE.SQUARROSA(205)//BORL95/3/2*MILAN), Ganj (NAC/TH.AC//3*PVN/3/MIRLO/BUC/4/2*PASTOR), Mehrgon (SAAR/WAXWING), Sipar (FRET 2*2/4/SNI/TRAP #1/3/KAUZ*2/TRAP//KAUZ/5) and Lochin (PJN/BOW//OPATA*2/3/CROC_1/AE.SQ.(224)).