Punjab Agricultural University
Parampreet,Kaur, Preeni, Bawa, Bharat, Yadav, Ajay, Mahato, Inderjit, Yadav, Priti, Sharma, OP, Gupta, Parveen, Chhuneja, NS, Bains, Jaroslav, Dolezel, Bikram Singh, Gill, J, Khurana, NK, Singh, Kuldeep, Singh, Kelly, Eversole
Diploid A genome wheat species harbor immense genetic variability which has been targeted and proven useful in wheat crop improvement. Further, the development and deployment of sequence based markers in wheat using survey sequences from next generation sequencing has opened avenues for comparative analysis, gene transfer and marker assisted selection (MAS) using high throughput cost effective genotyping techniques. Chromosome 2A of wheat is known to harbor several economically important genes. The present study aimed at in silico identification of genes corresponding to full length cDNAs and mining of SSRs and ISBPs from 2A draft sequence assembly of Chinese Spring for marker development. In totality, 1029 primer pairs (478 gene based, 501 SSRs and 50 ISBPs) were used to screen for polymorphism in diploid A genome species i.e., T. monococcum and T. boeoticum that identified 221 polymorphic loci. Out of these, 119 markers were mapped in T. monococcum X T. boeoticum RIL population. The enriched 2A genetic map constituted 161 mapped markers with final map length of 549.6 cM. Further, the utility of this enriched genetic map was demonstrated towards the fine mapping of adult plant resistance (APR) QTL, QYrtm.pau-2A against stripe rust. Using composite interval mapping, a QTL was detected between G45 and G54 markers explaining 19% of phenotypic variance. The primer sequences of the two genic markers were used to find the scaffold of 343 kb from IWGSC WGA V0.4 data. Thirty five simple sequence repeat markers were designed from the scaffold sequence which are being used for the fine mapping of QYrtm.pau-2A.
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.
International Center for Agricultrural Research in Dry Areas
Wuletaw,Tadesse, Najib, Bendaou, , , , , , , , , , , , , , , , , , , , , , , , , ,
Hybrid wheat is a promising technology to increase yields worldwide. High seed production costs and low heterosis are the main constraints for the development of hybrid wheats. Maximizing heterosis, and selection and utilization of appropriate morphological, floral and flowering traits to optimize outcrossing are important for hybrid seed production. For an efficient hybrid wheat seed production, high anther extrusion is required to promote cross fertilization and to ensure a high level of pollen availability. A pool of 200 elite spring bread wheat male parental lines was visually assessed for anther extrusion in the plastic-house and field environments. Genome-wide association studies (GWAS) for anther extrusion was carried out using a total of 12725 SNP markers. A wide genotypic variance was observed. Several significant (|log10(P)| > 3.0) marker trait associations (MTAs) were detected. Both genotypes and environment influenced the magnitude of the anther of extrusion. The consistently significant markers could be helpful to introduce anther extrusion trait in high yielding varieties and consequently improve hybrid-seed production in wheat.
Research Institute of Crop Husbandry, Azerbaijan
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A study was conducted between 2014 and 2016 aiming at determining resistance genotypes of 51 local wheat cultivars in Azerbaijan. The cultivars were evaluated in five different agro-ecological zone including Absheron and Tar-Tar (Irrigated area), Qobustan (dry semi subtropical area),Sheki (rain fed area), and Jalilabad (dry area) against three of the rust pathogens under natural conditions with four repetitions at each region. Field responses under natural infection were recorded according to Modified Cobb's scale for major field responses (Restance (R), Moderelt Resistance MR), Moderet Sesusptable (MS), and Sussciptabe (S) and diseases severity (0-100%). For molecular analysis, genomic DNA was extracted from leaves and the following six markers (Yr5, Yr9, Yr10, Yr15, Yr17, Yr18, and Yr26) were used to identify resistance genes at Plant Genomics College of Agronomy Northwest A&F University China. Marker analysis revealed that Yr5 was present at least in 12 cultivars including Murov, Murov-2, Shafag, Shafaq-2, Nurlu-99,Fatima, Azamatli-95,Agali, Gunashli, Saba Giymatli 2/17, P?rzivan-1, Tale-38. In addition, Yr9 was present in seven culitivars (Pirshahin-1, Layagatli-80, Shafag-2, Zirva-85,Fatima, Agali, Gunashli). Yr10 was present in eight cultivars (Yegana, Garagilchig-2, Yagut, Pirshahin, Shirvan-5, Barakatli-95, Bayaz, Girmizi bugda). And Yr18 was present in Mirbashir-128, Azamatli-95, Gunashli, Akinchi-84, Shirvan-3 cultivars. Yr26 worked well but was not found in any of cultivars. Yr17,Yr15 did not work very well with this method.
Crop Breeding Institute
Sripada,Udupa, Charles, Mutengwa, Peter, Mavindidze, , , , , , , , , , , , , , , , , , , , , , , ,
Host resistance is the most effective and economical method to minimize yield losses caused by rusts. The aim of this study was to detect the presence of resistance in 75 wheat genotypes. The presence of the genes viz. Sr2, Sr24, Lr34, Lr37, Lr46 and Lr68 was investigated using simple sequence repeat and sequence tagged site markers. Quantitative aspects of resistance to leaf rust were assessed through infection response (IR), disease severity (DS), coefficient of infection (CI), disease incidence (DI), leaf tip necrosis (Ltn) and area under disease progress curve (AUDPC) under natural epidemics. Highly significant (p <0.001) differences were observed among the genotypes for CI, DI, AUDPC and relative AUDPC (rAUDPC). Twenty genotypes exhibited high levels of adult plant resistance, recording CI less than 20% and AUDPC less than 300%, with moderately susceptible to susceptible reactions. The most frequently occurring gene was Lr46 (21%), followed by Lr68 (20%), Lr34 (19%) andLr37 (11%). The stem rust resistance gene Sr24 was absent in all the genotypes. Selection for Lr34 and Lr46 based on Ltn alone can sometimes be misleading because of its variable expression in different genetic backgrounds.
Anvar,Jalilov, Zubaida, Kavrakova, Menu, Mamadyusufova, Botirov, Muhiddin, , , , , , , , , , , , , , , , , , , , , ,
The wild relatives of wheat, the genus Aegilops is of great interest for breeding. Many species of the genus Aegilops are distinguished by such valuable properties as resistance to rust diseases, drought resistance, and salt tolerance.
The evaluation of local wheat varieties on resistance to yellow rust showed that local varieties showed high resistance to the pathogen and were amazed from 0 to 10 %. Evaluation of Aegilops species for resistance to yellow and brown rust, showed that the species Aegilops triunciales showed high resistance to yellow and brown rust, except Ae. triunciales, collected in the Rudaki district and showed moderate resistance to brown rust - 20%. The view of the Aegilops cylindrical collected in the Rudakinsky district showed a moderate resistance to yellow rust and a high resistance to brown rust. View Aegilops tauschii, collected in the Rudakinsky district had a high resistance to yellow and brown rust. Species Aegilops crassa to yellow and brown rust showed a reaction from moderate resistance - 30% to moderate susceptibility - 40%. As a result of the studies to assess the resistance of wheat varieties in Central Tajikistan, the cultivars Jaldak, Safedaki Gorchivin and Viyod, which had high resistance to yellow and brown rust, as well as Pamir and Surkhak varieties, showed moderate resistance.
Distinct varieties of wheat with high and moderate resistance to the pathogen of yellow rust can be used as parental forms for breeding new varieties of wheat. Studies on assessing the resistance of Aegilops species have shown that the species Aegilops triunciales has a high resistance to the pathogen of yellow rust. Species of Aegilops tauschii and Aegilops crassa, collected from the Hissar salt source, had moderate resistance to the pathogen. These species of Aegilops can be used in the selection of new varieties of wheat.
National Plant Protection Center
Thinlay (PhD),, Ugyen, Yangchen, , , , , , , , , , , , , , , , , , , , , , , , , ,
Wheat rusts are the important fungal diseases that limit the production and downgrade wheat quality. There are three types of wheat rusts; stem rust caused by Puccinia graminis f. sp. tritici, stripe rust caused by Puccinia striiformis f. sp. tritici and leaf rust caused by Puccinia triticina. The study was conducted to assess the susceptibility of Bhutanese wheat cultivars and differential lines to rust diseases at mid and low altitudes. The study was conducted in Mendagang for mid altitude (1,332 masl) and Samtenling for low altitude (378 masl) from December 2016 to March 2017. The experiment followed Randomized Complete Block design (RCBD) with 15 treatments (wheat lines) and three replications. However, only 11 lines germinated in both locations. Disease assessments were performed approximately at 60, 90 and 120 days after sowing following the modified Cobb?s disease rating scale. Only leaf rust was observed and the disease incidence ranged from 2.5 to 10% and 2.5 to 16% at mid and low altitudes respectively. Disease severity of 5 to 20%, corresponding to field response of immune to moderately resistant was observed at mid altitude; while 5 to 100% with immune to susceptible field response was observed at low altitude. There was a significant difference in disease incidence by site (p=.038) but not in disease severity (p=.129). The study also revealed that disease severity was positively correlated (r=.359); (r=.034); with mean minimum and maximum temperature respectively and (r=.361) with mean minimum relative humidity. All the correlations were highly significant (p=.003). The study found that ICARDA line 1 with severity (100%) was highly susceptible (100S) to leaf rust at low altitude while Bajosokha kaa remain an immune in both the locations. The results indicate that leaf rust can occur in both low and mid altitudes; however selection of suitable lines requires more extensive studies.
La Trobe University
Antony,Gendall, Hans, Daetwyler, Matthew, Hayden, , , , , , , , , , , , , , , , , , , , , , , ,
Wheat stem (Sr), leaf (Lr) and stripe (Yr) rust pathogens are among the most destructive fungal diseases threatening global wheat production. We utilized 2300 wheat accession including worldwide landraces, cultivars, breeding materials and 341 synthetic accessions backcrossed with three widely grown Australian cultivars (Annuello, Yitpi and Correll) to investigate rust resistance under wide environmental conditions. The germplasm was genotyped with 90K SNP chip, and was phenotyped for two seasons in three different environments against Sr and Lr and in four different environments against Yr. Different environments for each trait showed significant correlation with mean r values of 0.53, 0.23 and 0.66 for Lr, Sr and Yr; respectively. Single-trait genome wide association (GWAS) revealed several environment-specific QTL and multi-environmental QTL distributed on all chromosomes except 6D. Multi-trait GWAS confirmed a cluster of Yr QTL on chromosome 3B (within 8.3 cM) as well as a QTL for Sr and Lr on chromosome 3D. Linkage disequilibrium and comparative mapping showed that at least three Yr QTL exists within the 3B cluster including the durable rust resistance gene Sr2/Yr30. The same region was effective against Sr resistance but did not pass the stringent significant threshold in two environments. The 3D QTL was found mainly in the synthetic germplasm with Annuello background which is known to carry the Ag. elongatum 3D translocation carrying Sr24/Lr24 resistance gene. Interestingly, estimating the SNP effect using BayesR method showed that the correlation among the highest 5% QTL effects across environments were lower than that for the small effect QTL with differences in r values of 0.25 and 0.2 for Lr and Yr respectively. These results indicate the importance of small effect QTL that cannot be captured using GWAS in achieving durable rust resistance. The detected QTL in this study are useful resources for improving bread wheat resistance to rust diseases.
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.
Mohamed 5th University / ICARDA
Samir,Alahmad, Ayed, Al-Abdallat, Lee, Hickey, Abdelkarim, Filali-Maltouf, Bouchra, Belkadi, Filippo, Maria Bassi, , , , , , , , , , , , , , , , , ,
Durum wheat (Triticum durum Desf.) is a major cereal crop grown globally. The terminal reduced moisture and heat occurring at the flowering phase are among the main constraints to its production. The molecular basis of tolerance to these threats remains mostly unknown. A subset of 100 genotypes derived from a collection of 384 accessions originating from different countries were investigated for their root growth and architecture under water-limited and well-watered treatments. Two protocols were used, "clear pot" for seminal root angle and "pasta strainer" for mature root angle evaluation. This study reveals that root architecture did not change depending on water treatment. A genotypic variation in root angle was found and two categories of root types were identified: genotypes with (i) superficial and (ii) deep rooting systems. In order to investigate the impact of each root type on yield, all genotypes were tested in the field at multiple locations and under different water regimes. The same set was also tested for heat tolerance in the field under rainfed conditions. Heat was imposed by placing a polytunnel at flowering time to raise the temperature of 10 degrees. The yield, thousand kernel weight and grain number per spike, were evaluated and compared to assess grain fertility, considered as a key trait of heat tolerance. The complete set was genotyped and a genome scan using 8173 SNPs markers developed by 35K Axiom array allowed to identify the genomic regions influencing drought and heat adaptation mechanisms. The pyramiding of this genomic regions could lead to an improved resilience to climate change and increase durum wheat productivity.