Kazakh National Agrarian University
Yerlan Dutbayev, Alexei Morgounov
Kazakhstan is among the ten largest grain exporters in the world. Winter wheat in Kazakhstan is mainly cultivated in the southern and south-eastern regions on an area of 1.5-2 million hectares, including 140-170 thousand hectares - in irrigated lands. Annual losses of wheat yield from diseases can reach up to 30-40% or more. For Kazakhstan, the most dangerous diseases of winter wheat are stripe rust and leaf rust. Work is under way in Kazakhstan to find new donors for resistance to leaf rust and stripe rust and the use of these donors in breeding. The aim of this research was to expand genetic diversity through crosses and development of lines obtained by the method of remote hybridization, as well as selection of new sources of resistance of bread wheat to leaf rust and stripe rust in southeast Kazakhstan. The subject of the research were 49 hexaploidsynthtic lines of Kyoto University (Japan) and CIMMYT and commercial varieties of winter wheat in the Almaty region. We screened synthetic hexaploid wheat for resistance to diseases. A collection of hexaploid synthetic wheat lines resistant to the diseases and adapted to various conditions of the Almaty region has been established. The character of inheritance of resistance to diseases in crosses of synthetic wheat with local cultivars based on comparison of the first generation and parents was studied. Evaluation of phenotypes inheritance of resistance in hybrids in the generation of F2, showed that 9crosses of synthetic wheat(LANGDON/IG 48042//ZHETISU, LANGDON/IG 48042//FARABI, LANGDON/KU-20-8//AJARLY, LANGDON/KU-2075//AJARLY, LANGDON/KU-2097// ZHETISU, LANGDON/KU-2075//FARABI, LANGDON/KU-2100//STEKLOV, LANGDON/KU-2144//NAZ, LANGDON/KU-2076//NAZ)possess the dominant resistance genes to leaf rust.Seven lines(LANGDON/ KU-2075/AJARLY, LANGDON/KU-2075/FARABI, LANGDON/KU-2092/FARABI, LANGDON/KU-2100/NAZ, LANGDON/KU-2097/STEKLOVINDAYA, LANGDON/KU-2097/ZHETISU, LANGDON/KU-2097/ AJARLY) possess from one to several dominant resistance genes to stripe rust.
The University of Agriculture, Peshawar, Pakistan
Muhammad Khan, Muhammad Ismail, Sher Nawab, Abdullah Jalal, Muhammad Imtiaz, Sajid Ali
Rust disease response is used to assess the resistance status of breeding lines, which is required to be tested across location and complemented with molecular markers. The current study was designed to characterize yellow rust resistance in 29 introduced advanced CIMMYT wheat lines along with three check varieties across three contrasting wheat growing regions (Peshawar, Mansehra and Lakki-Marwat) during wheat season 2015-16. A high disease pressure was observed across all three locations as favorable cold and wet climatic conditions prevailed during 2015-16. The maximum disease was recorded at Mansehra (up to 90%) followed by Peshawar (up to 50%) and Lakki-Marwat (up to 45%). There was a significant variability amongst the tested wheat lines for yellow rust severity and in yield potential. Among the advanced lines, W-SA-104, W-SA-115 and W-SA-118 had better grain and biological yield. Based on disease and yield parameters, cluster analysis of 29 wheat lines along with three checks grouped wheat lines into four clusters. None of these wheat lines showed resistance at every location (Average coefficient of infection "ACI" = 0). The maximum co-efficient of infection (55) was recorded at Mansehra whereas the minimum (0) was recorded at Peshawar and Lakki-Marwat. Twenty-six of these wheat lines were identified to possess partial resistance to yellow rust (with ACI < 20). Genotyping for the presence of resistance gene markers STS-7 (linked with Yr5), SC-Y15 (linked with Yr17) and Xwmc-44 (linked with Yr29) revealed the highest frequency of Yr17 (90.60%), followed by Yr29 (87.5%) and Yr5 (50%). The three resistant genes together were present only in 15 wheat lines (46.87%). Our results thus revealed the presence of variation in resistance response based on both field testing and molecular markers which could be utilized in wheat breeding to develop better resistance varieties to be exploited at field level.
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.
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 Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences
Shahriyar Sadigov, Alamdar Mammadov, Irada Huseynova
Rust of cereals are considered to be an important disease in many countries, including Azerbaijan. One of these is stem rust caused by Puccinia graminis f. sp. tritici (Pgt). Extensive research on the identification of wheat stem rust resistance genes and effectiveness of these genes in various geographical regions have been conducted. Genetic resistance is one of the most effective ways for controlling stem rust. Sixty-nine stem rust resistance genes (including 45 identified Sr genes and 24 genes with temporary designations) are registered in the Komugi Wheat Genetics Resource Database. It is important to use proper combinations of resistance genes in developing lasting resistance wheat. The main purpose of the study was to identify lines caring Sr11, Sr26 and Sr31 genes, which are effective to the predominant Pgt races in Azerbaijan. Durum and bread wheat genotypes differing in their disease resistance, productivity and other physiological traits were chosen from the wheat gene bank of the Research Institute of Crop Husbandry (Baku, Azerbaijan) for analysis. DNA extraction was carried out according to standard CTAB protocol. RT-PCR performed using KASP markers (KASP_6BL_BS0074288_51 and KASp_6BL_Tdurum contig55744_822) identified nine durum genotypes (out of 34 genotypes) and seven wheat genotypes (out of ten genotypes), caring Sr11. Using the dominant STS marker (Sr26#43) a diagnostic 207 bp amplicon for Sr26 gene, was observed in 11 of the 42 wheat genotypes tested. In eight of the 42 wheat genotypes tested, the diagnostic 1,110 bp amplicon was observed using the Lr26-Sr31-Yr9 locus specific marker iag95, characteristic of Sr31 gene located at 1BL.1RS translocation. For the first time, wheat germplasm in Azerbaijan was analyzed using KASP genotyping technology and genetic resources, and resulted in the identification of wheat lines with effective resistant to Puccinia graminis f. sp. tritici race TKTTF.
Sathguru Management Consultants
Kanan,Vijayaraghavan, Vijay, Paranjape, Richa, Kapur, Vignesh, Vilayanur Jayaraman, , , , , , , , , , , , , , , , , , , , , ,
Wheat is one of the most important food crops of the world. India is the second largest producer of wheat, currently producing 95 million tons from about 30 million hectares. Looking ahead to 2050, India needs to constantly increase production to about 150 million tons, to meet the rising population and demand. With area under cultivation having no room for growth, productivity will be the main pillar for growing production. Currently India?s yield of 3.1 t/ha has plenty room for growth as compared to the world leaders such as France (7.5 t/ha), Germany (7.3 t/ha) and UK (6.6 t/ha). Wheat productivity depends on multiple factors, seed being one of the most important.
The current operating environment is characterized by wheat R&D in the country conducted by public institutes, but there are clear signs of an emerging private sector involvement. The government promoting Inter-institutional linkages by way of associating private players in research and seed production.
This study evaluates and reflects on the current situation of the wheat seed sector in India - from research, variety/hybrid development, seed production, indent to distribution, the players involved, the challenges therein, upcoming technologies and the way forward.
Wheat Dis. Res. Dept., Plant Pathol. Res. Inst., A.R.C., Sakha, Egypt
Les John Szabo
Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most serious disease of wheat worldwide. The discovery of new Pgt races in Africa, Ug99 and its variants, brings a new threat to global wheat production. In this study, 50 single pustule stem rust samples, were collected during 2015-2016 from the International Stem rust Trap Nursery (ISRTN) and commercial wheat fields in Sakha, the most important wheat growing region in Egypt. SNP-genotyping was carried out at USDA-ARS Cereal Disease Laboratory. Infection and genotype data confirmed that none of these samples belonged to the Pgt Ug99 race group. Forty-five samples were successfully genotyped consisting of 12 multi-locus genotypes (MLGs). The majority (86.7%) of the samples belonged to three clades: 10 samples, clade III-B (MLG.04, race TTRTF) collected from Misr 3, Sakha 95 and Sids 14 wheat lines; 12 samples, clade IV-A.2 (MLG.06, race TKTTF) collected from Sr 5, Sr6, Sr7a, Sr7b, Sr8b, Sr9a, Sr9e, Sr10, Sr11, Sr15, Sr16 and Sr17 wheat lines; 17 samples, clade IV-E.2 (MLG.11, race TKKTF) from Sr13, Sr14, Sr19, SrMcN, Sr24, Misr 1, Misr 2, Sakha95 and Sids 12 wheat lines. Pgt samples belonging to clades IV-A.2 and IV-E.2 have been observed from Europe to the Middle East, and samples from clade III-B from the southern Caucasus Mountains, Middle East to northeast Africa. The remaining six samples collected from Sr12, Sr18, Sr20, Sr21, Sr22 and Sr25 wheat lines represent two new genotypes (MLG.14 and MLG.17) that have not been assigned to clades. MLG.14 was also observed in samples from Azerbaijan, Iraq and Eritrea. In contrast, this represents the first detection of MLG.17. These results suggest continued variability of the Pgt population in Egypt therefore, emphasizing the importance regularly monitoring to timely identify new races, and utilize this information in screening and identification of effective sources of resistance.
Institute of Plant Protection, Chinese Academy of Agricultural Sciences
Jing Feng, Ruiming Lin, Fengtao Wang, Qiang Yao, Qingyun Guo, Shichang Xu
Wheat stripe rust is an important air borne disease caused by Puccinia striiformis f. sp. tritici, and seriously threatens the safety of wheat production. Breeding and utilization of resistant varieties is the most economical, safe and effective measure to control wheat stripe rust. Sifangmai is a landrace from the state of Guangxi, China, and maintains good resistance to the current epidemic species CYR34, CYR33, CYR32 and CYR29 in China. Sifangmai was crossed with Taichung 29 to obtain F1, F2 and F2:3 to analyze its character of inheritance. In the adult stage, the cross of Sifangmai /Taichung 29 was inoculated by CYR32. The genetic analysis showed that the resistance of Sifangmai to CYR32 was controlled by a dominant gene, named as YrSF. A mapping population of F2 was genotyped with simple sequence repeat (SSR) markers. SSR loci Xgpw8015, Xgpw4098, Xwmc73, Xgpw8092, Xgpw7309 and Xbarc89 on 5B chromosome showed polymorphic between Taichung 29, Sifangmai, and resistant and susceptible pools, indicating that the resistant gene in Sifangmai was located on the 5B chromosome. The linkage map of these SSR markers was constructed and the nearest SSR to the gene is Xgpw8015. A set of Chinese Spring nulli-tetrasomic lines was used to confirm YrSF on chromosome 5B. YrSF is different from known genes in chromosome 5B. Xgpw8015 can be used as a marker for detection of YrSF.
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.
University of Minnesota
Michael Pumphrey, Matthew Rouse
Stem rust of wheat caused by the fungal pathogen Puccinia graminis f. sp. tritici historically caused major yield losses of wheat worldwide. To understand the genetic basis of stem rust resistance in contemporary North American spring wheat, genome-wide association analysis was conducted on 250 elite lines. The lines were evaluated in separate nurseries each inoculated with a different P. graminis f. sp. tritici race for three years (2013, 2015 and 2016) at Rosemount, Minnesota. The lines were also challenged with the same four races at the seedling stage in a greenhouse facility at the USDA-ARS Cereal Disease Laboratory. A total of 22,310 high-quality SNPs obtained from the Infinium 90,000 SNPs chip were used to perform association analysis. Markers strongly associated with resistance to the four races at seedling and field environments were identified. At the seedling stage, the most significant marker-trait associations were detected in the regions of known major genes (Sr6, Sr7a and Sr9b) except for race QFCSC where a strong association was detected on chromosome arm 1AL. Markers presumably linked to Sr6 and Sr7a were associated with both seedling and field resistance to specific races. A field resistance QTL on chromosome arm 2DS was detected for response to races RCRSC and TPMKC. A QTL specific to field resistance was detected for QFCSC and TPMKC on 2BL. The markers that showed strong association signals may be useful to pyramid and track race-specific stem rust resistance genes in wheat breeding programs. We postulated the presence of Sr2, Sr6, Sr7a, Sr8a, Sr9b, Sr11, Sr12, Sr24, Sr25, Sr31, and Sr57 (Lr34) in this germplasm based on phenotypic and marker data. We found that combinations of genes conferring resistance to specific P. graminis f. sp. tritici races accounts for the prevalent stem rust resistance in North American spring wheat.