Global Rust Reference Center (GRRC), Aarhus University, Denmark
Mogens Støvring Hovmøller, Jens Grønbech Hansen, Annemarie Fejer Justesen, Tine Thach, Julian Rodriguez-Algab, Dave Hodson, Biagio Randazzo
In 2016, severe epidemics of yellow (stripe) rust were observed on durum and bread wheat in European regions where the diseases in the past were insignificant or absent. Stem rust was also observed at epidemic levels for the first time in more than 50 years in Europe. On Sicily, both yellow and stem rust caused epidemics on cultivated durum and bread wheat and numerous breeding lines. In 2017, surveys in farmer fields and trial monitoring were carried out in Southern Italy during April-June. A total of 61 farmer fields and 9 experimental plots were inspected and rust samples collected. Despite unfavourable weather conditions for rust development, stem rust, yellow rust and leaf rust were detected on 86%, 50% and 14% of the surveyed sites, respectively. The surveys on Sicily covered approximately 70% of the durum wheat area, and data uploaded and visualised on the Wheat Rust Toolbox. On mainland Italy and Sardinia, yellow rust was observed, and sampled from nine fields in Sardinia and two in Puglia, whereas stem rust was detected and sampled in experimental plots in Sicily, Sardinia, Puglia, Lazio and Emilia Romagna. A total of 94 samples of stem rust, 30 samples of yellow rust, and 3 rust samples from Berberis aetnensis were sent to GRRC. Preliminary results of yellow rust genotyping and race phenotyping showed prevalence of race Triticale2015. Warrior(-) and a new race (Pst'New'- First detected in 2016) were also detected. For stem rust, TTTTF and TTRTF were detected in Sicily and mainland Italy and TKTTF was identified in Sardinia. Susceptibility of major commercial durum cultivars and breeding lines suggests the need for both durable resistance breeding and systematic surveys coupled to an early warning system.
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.
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.
Lake Chad Research Institute, Maiduguri, Borno State-Nigeria
Dattijo Aminu, Zakari Goji Silas Turaki, Fatima Henkrar, Udupa Sripada
The research was conducted at ICARDA, Rabat. Twenty-four accessions were obtained from LCRI for marker analysis. Wizard Genomic DNA Purification Kit was used for DNA extraction. DNA was extracted by CTAB method and quantified using 1.0 % (w/v) agarose gels. Total of 12 loci, 5 functional and 7 linked random DNA markers to the traits of interest were used. PowerMarker and DARwin software were used to calculate the No. of alleles and values of genetic diversity, PIC, genetic distance, and NJ dendrogram. The total No. of detected alleles was 39; and mean No. of alleles was 3.25. No. of alleles range from 1 (Dreb-B1) to 9 (Xgwm577). Genetic diversity index ranged from 0.0000 in Dreb-B1 to 0.8471 in Xgwm577. The PIC value was also varied from 0.0000 (Dreb-B1) to 0.8296 (Xgwm577). The frequency of biotic resistance linked random DNA marker allele at Xgwm144 and Xwmc44, associated with yellow and leaf rust gene was 25% each. Marker alleles Xgwm577 and Xgwm533 linked to Stb2 and Stb8 at 150 and 120bp have frequencies of 21 and 4%. The frequency of abiotic resistance showed 50% of accessions had 1R segment (1BL.1RS translocation) and 58% of accessions showed presence of 120bp allele of Xwmc89, associated with QTL for drought tolerant. Functional marker alleles of Dreb-B1 associated with drought tolerant genes showed alleles frequency in all accessions. Linked marker allele Xgwm111 linked to heat tolerant gene showed 17% allele frequency at 220bp. Rht1 and Rht2, the allele frequencies were 92 and 4%. 92% of the cultivars had photoperiod insensitive allele at Ppd-D1 locus. VrnA1a and VrnA1c primer pair amplified at 965, 876, and 484bp, allele frequency of 13 and 87%. Cluster analysis had grouped the accessions into 5 at a genetic distance level 0.15.
John Innes Centre
Burkhard,Steuernagel, Caixia, Lan, Miroslava, Karafi?tov?, Ksenia, Krasileva, Jaroslav, Dole?el, Evans, Lagudah, Ravi, Singh, Brande, Wulff, , , , , , , , , , , , , ,
Adult Plant Resistance (APR) genes are broad-spectrum, partial-resistance genes that have the potential to contribute to sustainable control of wheat rust diseases. However, their isolation and characterization are complicated by the lack of precise molecular markers required for their identification, and therefore their use in plant breeding programs has been limited. Recent developments including the falling cost of sequencing and the increasing use of sequence capture methods to reduce genome complexity have enabled previously intractable methods such as mutational genomics to clone genes in wheat. Despite their increasing ease of use, many of these approaches require prior knowledge of the gene space and, in some cases, the gene family of the target gene to be cloned. As the APRs cloned so far do not belong to any common gene family, it is not possible to use general features of these identified APRs to conduct biased searches for novel APRs. This project aims to use an unbiased gene isolation technique called MutChromSeq, which combines chromosome flow-sorting and mutational genomics, and is independent of fine mapping, to rapidly clone the recently discovered APR gene Lr68 (Leaf Rust 68). Cloning APRs allows breeders to trace genes cheaply and quickly using gene-specific markers, enabling them to build effective and durable resistance gene pyramids. It also allows us to elucidate any common mechanism of action they have, helping researchers and breeders understand better the basis of their durable resistance. At the same time, the generation time of wheat has become one of the major limiting factors for the response time of breeders to rust epidemics. Thus, this project also aims to combine marker-assisted selection with accelerated generation advancement ('speed breeding') for rapid germplasm structuring and field performance evaluation.
John Innes Centre
Christopher,Judge, Francesca, Minter, Nik, Cunniffe, Richard, Morris, Diane, Saunders, , , , , , , , , , , , , , , , , , , ,
Wheat yellow rust is a disease caused by the fungus Puccinia striiformis f. sp tritici (PST) that is a significant threat to wheat production worldwide. Recently, a novel approach called "Field Pathogenomics" was developed that allows acquisition of genotypic data from field samples of PST-infected wheat. This has enabled us to study the re-emergence of this pathogen in the UK and understand the different races that form the current PST population. However, the dynamics of pathogen transmission and dispersal still remain unknown and understanding this is essential for designing effective surveillance. The objective of this project is to develop a spatially-explicit model for the spread of PST that can contribute to better management of the disease and be used as a warning system for wheat yellow rust infection in the UK. The first aim is to study how PST spreads at the field level and determine whether there are differences between PST races in terms of disease dynamics. To this end, a set of markers have been designed that can be used to genotype field-collected isolates and determine which race they belong to. Field trials were also undertaken across the UK using wheat varieties that are known to be susceptible to the disease, with PST-infected wheat samples collected during the 2015-2016 and 2016-2017 seasons. These samples will be genotyped to study the prevalence of different PST races and determine whether PST genotypes identified early in the season are predictive of dominant genotypes found later in the season. Understanding PST dynamics within a field is key to build an epidemiological model that can predict how this disease behaves. This would improve disease management, targeting of chemical sprays and optimize pathogen surveillance.
National Plant Protection Center
Namgay Om, Thinlay, Ugyen Yangchen
Wheat rusts are one of the important diseases that limit the production and downgrade wheat quality. Three rust diseases of wheat are stem rust caused by Puccinia graminis Pers. f. sp. tritici Eriks., stripe rust caused by Puccinia striiformis Westend. f. sp. tritici Eriks., and leaf rust caused by Puccinia triticina Eriks. This study was conducted to determine the reaction of wheat varieties to wheat rusts at different altitudes. Field experiments were conducted from December 2016 to March 2017 at Mendagang (27.5886°N, 89.8711°E, 1332 masl), Punakha Dzongkhag (district) for mid altitude and at Agriculture Research and Development Center (ARDC), Samtenling (26.9058°N, 90.4308°E, 378 masl), Sarpang Dzongkhag, Bhutan for low altitude. The experiment followed a RCBD with 15 treatments comprising of three Bhutanese released varieties, eight SAARC varieties, and four ICARDA varieties. Each treatment was replicated three times. Assessment of disease incidence and severity were performed three times starting from tillering to ripening stage, approximately at 60, 90 and 120 days after sowing (DAS). Disease severity was determined following the modified Cobb’s disease rating scale. Of the 15 varieties, only 11 germinated in both the sites. Among the three wheat rust diseases, only leaf rust was observed in both sites. Leaf rust incidences 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 (5O) to moderately resistant (20MR), was observed at mid altitude, while 5 to 100%, with immune (5O) to susceptible (100S), 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 variety, ICARDA 1, with 100% severity was highly susceptible (100S) to leaf rust at low altitude while Bajosokha Kaa remained immune (5O) in both the sites. The results indicate that leaf rust can occur in both low and mid altitudes; however selection of suitable varieties requires more extensive studies.
Department of Agriculture, Sunsari, Nepal
Wheat (Triticum aestivum L.) is one of the major cereal crops vital for global food supply. Most of the wheat crop in developing world including that of Nepal is either grown with limited irrigation or under rainfed conditions and thus face moisture stress at one or more growth stages limiting grain yield. An experiment was carried out at the Institute of Agriculture and Animal Science, Rampur to evaluate the genetic variability of selected drought adaptive traits in Nepalese wheat germplasm. The wheat genotypes evaluated comprised of Nepalese landraces and commercial cultivars, CIMMYT (International Center for Maize and Wheat Improvement) derived advanced introduction lines and three checks with differential drought adaptability. The wheat genotypes were grown in pots (single plant) arranged in a replicated split plot design in greenhouse under two contrasting moisture regimes, optimum and moisture stressed. The genotypes were evaluated for water use, water use efficiency, relative leaf water content and biomass production. The ANOVA (Analysis of Variance) revealed significant variation between environments and among the wheat genotypes for most of the traits studied. A wide range of variability was observed for water use, water use efficiency, biomass yield and relative leaf water content in moisture stressed and non-stressed environments. Nepalese cultivar Gautam showed a number of favorable drought adaptive traits, whereas, Bhrikuti was average in this respect. Based on the scores of drought adaptive traits recently released Cultivar (cv). Vijay was characterized as drought sensitive. A number of landraces and advanced breeding lines showed high level of water use efficiency and other positive traits for drought adaptation.
Fatima Gaboun, Nasserlhaq Nsarellah, Keltoum Rhrib, Atmane Rochdi
Durum wheat landraces have constituted the main source of Moroccan wheat production until the first half of the last century. This local germplasm is still cultivated in less favorable environments particularly in mountains and sub-Saharan regions. In recent decades of the late 20th and early 21th centuries, the genetic improvement had led to the release of new durum wheat cultivars highly uniform and more productive. The present paper investigates the evolution of genetic variability in terms of productivity and quality related traits using an historical series of Moroccan durum wheat genotypes grouped according to their period of release into "Landraces/ Old cultivars," "Intermediate cultivars," and "Modern cultivars". A significant improvement was achieved in durum wheat Morroccan productivity. Modern cultivars exceed their predecessors in terms of productivity related traits. The genetic gain was clearly associated with a reduction in plant cycle and plant height lowering the straw yield which resulted in an increase of grain yield estimated to 15.42Kg/ha/year. However, results revealed a reduction in terms of almost all quality related traits; -0.12% per year for protein content, -0.30 % per year for gluten strength, -0.31% per year for yellow pigment content, and -0.19% per year for vitreousness. The results underline the important variability in grain quality attributes among landraces genotypes. This local germplasm may be used as sources of quality-improving attributes in durum wheat breeding program to develop new varieties combining both high productivity and grain quality.
Ravi,Singh, Julio, Huerta-Espino, Mandeep, Randhawa, , , , , , , , , , , , , , , , , , , , , , , ,
Wheat leaf rust (LR) and stripe rust (YR), caused by the air-borne fungi Puccinia triticina (Pt) and Puccinia striiformis f. sp. tritici (Pst), respectively, are considered the primary biotic threats to bread wheat and durum wheat production globally. Growing resistant wheat varieties is a key method of minimizing the extent of yield losses caused by these diseases. Bread wheat lines Francolin #1, Kenya Kongoni, Kundan and Sujata, and CIMMYT-derived durum wheat lines Bairds and Dunkler display an adequate level of adult plant resistance (APR) to both leaf rust and stripe rust in Mexican field environments. Six recombinant inbred line (RIL) populations developed from crosses Avocet/Francolin #1, Avocet/Kenya Kongoni, Avocet/Kundan, Avocet/Sujata, Atred#1/Bairds and Atred#1/Dunkler were phenotyped for leaf rust response at Ciudad Obregon, Mexico, and the bread wheat populations for stripe rust response at Toluca for under artificial inoculations for multiple seasons. The RIL populations and their parents were genotyped with the 50 K diversity arrays technology (DArT) sequence system and simple sequence repeat (SSR) markers. Known pleotropic APR genes Lr46/Yr29 mapped in all of six populations, and explained 7.4-65.1% and 7.7-66.1% severity variations for LR and YR across different bread wheat populations and accounted for 12.4-60.8% of LR severity variations over two durum wheat populations. In addition, several new APR loci identified on chromosomes 1AS, 1DS, 2BS, 2BL, 3D and 7BL in bread wheat and QTL on chromosome 6BL in durum wheat. Among these loci, QTL on chromosomes 1AS, 3D and 7BL might be represent new co-located/pleotropic loci conferring APR to LR and YR. RILs combining these APR loci can be used as sources of complex APR in both bread wheat and durum wheat breeding. In addition, the closely linked single nucleotide polymorphism (SNP) markers have been converted into breeder-friendly kompetitive allele specific PCR (KASP) markers and their diagnostic verified.