University of Agriculture, faisalabad
Drought tolerance is a polygenic trait, with a complicated phenotype, often confused by plant phenology. Breeding for water stress is more complex since there are many types of abiotic stresses, such as drought, heat and salt. High yielding wheat genotypes viz., Miraj-06, 9452, 9469, 9272, 9277, CMS-127 and three testers Chakwal-50,
Kohistan-97 and Aas-11 were crossed in line ? tester mating design. Seed obtained from crosses was evaluated in field conditions for various agronomic traits under drought conditions. Recorded data were subjected to analysis of variance to determine the genetic variability. The data were analyzed statistically and combining ability
studies were tested using line ? tester analysis to find the relationship between different traits of wheat. High significant differences were observed among the lines and testers for yield related traits under stress conditions.
The female line 9452 proved to be best line on the basis of mean performance of traits under water stress. In case of testers, the male parent variety Chakwal-50 retained its performance in maximum number of traits closely followed by Aas-11. The cross combination 9272 ? Aas-11 proved best for attaining highest mean for most of
traits. In case of GCA effects line 9277 and tester Aas-11 proved best. The cross combinations 9277 ? Chakwal-50, 9452 ? Kohistan-97 exhibited highest SCA effects. The superior genotypes and crosses can be combined to develop new promising and improved varieties under water stress conditions.
Crop Development Centre/Department of Plant Science, University of Saskatchewan, Saskatoon, Canada
Sajid Ali, Dinah Qutob, Steve Ambrose, Ron Maclachlan, Kun Lou, Curtis Pozniak, Yong-Bi Fu, Andrew Sharpe, Randy Kutcher
Puccinia striiformis f. sp. tritici (Pst), the cause of wheat stripe rust, is one of the most important pathogens of wheat. Attempts have been made in the past to characterize the worldwide genetic structure of Pst populations, excluding Canada. Characterization of 59 isolates identified 33 races with three most common races representing half of the population and subtle differences in races of eastern and western prairies. For molecular characterization, 48 isolates were sequenced to obtain SNPs and genotyped with Pst-specific SSR markers. Isolates that were suspected of recombination based on SNP data were examined for their telia production ability as a proxy for sexual recombination. The study revealed that the majority of the population was clonal, however, not exclusively clonal, with the existence of four genetic lineages. Two lineages previously reported were identified: PstS0, representing an old northwestern-European and PstS1, an invasive warmer-temperature adapted lineage. Additionally, two new lineages, PstPr and PstS1-related, were detected that have not been reported previously. The PstPr and PstS1-related lineages produced more telia than the other lineages and had double the number of unique recombination events compared to PstS0 and PstS1. PstPr was concluded to be a sexual recombinant and an exotic incursion, which was closely associated with PstS5, PstS7 (Warrior), and PstS8 (Kranich) lineages, all of which arose by sexual recombination in the center of diversity - the Himalayan region. The total phenotypic variation in the population could not be explained solely by molecular genotypes, and a hypothesis on existence of epigenetic machinery in the Pst genome was tested. Homologs of the DNMTases class (DNMT1) were identified, providing compelling evidence of a role for DNA methylation. As a first report of DNA methylation, an average of ~5%, 5-methyl cytosine (5-hmC) in the Puccinia epigenome indicated the possibility of epigenetic regulation, which merits further investigation.
ICAR-Indian Institute of Wheat and Barley Research
Sudheer Kumar, P.L. Kashyap, Gyanendra Pratap Singh
Yellow rust of wheat caused by Puccinia striiformis Westend. is one of the important diseases of wheat in India. In north Indian states it spreads quite fast due to favourable temperature and moisture prevailing in these states during major part of crop growth (November-mid March). In spite of favourable weather, proactive survey and surveillance and advisories issued in time resulted successful management of yellow rust in India during past four decades. Even large scale cultivation of varieties like HD 2967 in about 12 million ha past two years did not result any losses. Three spots of initial foci near foot hills in Punjab have been identified and are monitored regularly. Any sign of yellow rust is controlled effectively with the foliar sprays of fungicides like propiconazole @ 0.1%. Use of mobiles phones and internet services is regularly done for transfer of information on wheat crop health and suggestions for proper management. Strategic planting and sowing of wheat in which newly released high yielding yellow rust varieties helped in reducing the yellow rust inculum build up. Regular monitoring of wheat health via weather forecasts take place after every fortnight from December to March. During 2016-17 crop season, yellow rust was effectively managed and its occurrence was delayed in Punjab, Haryana and Uttarakhand states. Two new pathotypes, 110S 119 and 110S 84 developed recently were used for evaluation of entries of wheat yield trials during 2016-17 at hot spot locations. The new varieties in pipe line of identification and release are tested against yellow rust. The most critical period for yellow rust management remained from December till mid February.
Wheat Program, National Agricultural Research Center (NARC) Islamabad
Sikander Khan Tanveer, Muhammad Sohail, Muhammad Shahzad Ahmed, Sayed H. Abbass, Sundas Wagar, Atiq Rattu, Muhammad Imtiaz
Wheat plays a vital role in multifaceted farming system of Pakistan. Like other many other countries, Pakistan's sustainable wheat production is also continuously threatened by a number of biotic and abiotic stresses. Among the biotic stresses, three rust diseases of wheat have been the most devastating. Stem rust was effectively controlled with adoption of the semi-dwarf spring wheats of the Green Revolution. However, the threat of the evolution of Ug99 race of stem rust in East Africa and its migration to Iran cannot be neglected. The Chance of of Ug99 migrating from Iran into Pakistan, coupled with the presence of dangerous new races of stripe and leaf rusts invites enormous efforts for development of rust resistant varieties for sustainable production of the wheat in the country. In this regard the Wheat Program, NARC, Pakistan initiated an intensive breeding program with financial and technical support of USDA and CIMMYT. Diverse sources of resistance to the three rusts particularly to the stem rust race Ug99 were introduced from CIMMYT. Through the rigorous selection procedure, four rusts resistant wheat varieties (NARC 2011, Pakistan 2013, Zincol 2016 and Borlaug 2016) have been released. These varieties are also resistant to Ug99. The varieties i.e. NARC 2011, Borlaug 2016 and Zincol 2016 are performing well in irrigated areas whereas Pakistan 2013 is suitable for rainfed conditions. The variety Zincol 2016 has high Zn content (35 ppm) in grain as compared to national standard check variety (25 ppm). These varieties are not only higher yielding but also possess good grain quality and other desirable traits. A considerable quantity of seed of the varieties is already present in the national seed system and will reduce the risk of Ug99 threat.
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.
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.
Instituto Nacional de Tecnologia Agropecuaria (INIA), Estaci?n La Estanzuela, Ruta 50, Km 11, Colonia, Uruguay
Vanesa,Domeniguini, N?stor, Gonz?lez, Richard, Garcia, Carolina, Saint-Pierre, Pawan, Singh, Mart?n, Quincke, Silvia, Pereyra, Silvia, Germ?n, , , , , , , , , , , , , ,
Since 2014 CGIAR-WHEAT Program has promoted the establishment of a network of field-based Precision Wheat Phenotyping Platforms (PWPP) to expand the existing collaborations between CIMMYT, ICARDA and National Agricultural Research System partners. The main goals are improving the quality of data collected and shared among institutions to enhance and accelerate the international wheat breeding, and promote synergism with the private sector and nongovernmental organizations. In 2015, the PWPP-Uruguay was established to test genotypes for multiple diseases: leaf rust, Fusarium head blight and Septoria tritici blotch. These diseases are phenotyped each year in separate field trials artificially inoculated with pathogen isolates identified as representatives of the pathogen regional population. Wheat material is sowed in plots with susceptible checks every 50 entries. Disease severity and other variables related to the disease development are measured using standard international scales at dates when the expression of plant resistance is optimal. In the first three years of the platform, more than 1500 genotypes were screened per year. These materials had diverse origins (more than eight institutions, public and private, from eight countries) and diverse types: from recent commercialized to ancient cultivars, advanced lines, International CIMMYT nurseries, mapping populations or panels. Highly resistant genotypes to multiple diseases could be selected. At the present time, we are developing and adopting advanced phenotyping methods, combining remote sensing and image analysis, and exploring their adaptation to breeding constraints. Also, extension activities as internships, training courses and student projects are being developed. Major future prospects are the enhancement of data and germplasm exchange between platform partners and the PWPP network and the involvement in collaborative phenotyping/genotyping breeding projects.
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.
ICAR- Indian Institute of Wheat & Barley Research, Karnal-132001, India
Vinod Tiwari, DP Singh, RP Gangwar, GP Singh
The changing climatic conditions are affecting wheat production in major agro-ecological zones in India, namely, north western plains(NWPZ), north eastern plains(NEPZ), central (CZ) and peninsular zone(PZ) where the reproductive phase has to endure higher temperatures. Also, the prevalence and virulence of rust pathotypes and other diseases are affected. To address such challenges, development of wheat for climate resilience was initiated following shuttle breeding approach for incorporating heat stress tolerance as well as resistance to wheat rusts. During 2010-16, a total of 583 elite lines were evaluated against prevalent pathotypes of stripe rust 78S84, 110S119, 110S84 and 46S119; leaf rust 12-2(1R5), 12-5(29R45), 77-2(109R31-1), 77-5(121R63-1), 77-9(121R60-1) and 104-2 (21R55) and stem rust 11(79G31), 40A(62G29), 42(19G35), 122(7G11) and 117-6(37G19) of which 108 promising entries were identified. These lines were evaluated for disease response in multilocational Initial Plant Pathological Screening Nursery (IPPSN) against prevalent races of all three rusts. Based on average coefficient of infection (15.0 ACI), 42 (39%), 104 (96%) and 90(83%) entries were found resistant to different races of stripe, leaf and stem rusts, respectively. Based on performance in multiplication yield trials, 29 entries were contributed in national coordinated evaluation system on Wheat & Barley which resulted in release of four wheat cultivars DBW71(Yr9+27+,Lr26+,Sr2+5+31+), DBW107(Yr9+,Lr26+3+,Sr31+), DBW110(Yr2+, Lr13+10+,Sr13+11+) and DBW93(Yr9+, Lr26+23+, Sr31+) for commercial cultivation in NWPZ, NEPZ, CZ and PZ, respectively. These cultivars are becoming popular among farmers due to their yield advantage, resistance to diseases, tolerance to high temperature and better quality traits. Also, DBW 129 was screened in multiple disease screening nursery (MDSN) and observed resistant to all rusts, leaf blight, powdery mildew, flag smut and shoot fly. The adoption of the newly developed cultivars for deployment of differential genes for resistance would lead to reduction in disease pressure and bring higher profitability to farmers in different agro-ecological zones in India.
Wheat Research Centre, Bangladesh Agricultural Research Institute
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The soils of the entire Sylhet region of Bangladesh are strongly acidic where lands remain fallow during winter season due to scarcity of irrigation water required for rice cultivation. There is a scope of wheat expansion in this region as the water requirement of wheat is less than Boro rice. Field experimens were carried out at South-Surma, Sylhet, in 2012-13 and at FSRD site Jalalpur, Sylhet in 2013-14, in collaboration of WRC and OFRD. BARI examined the response of seven wheat varieties at two levels of lime in split-plot design where lime was applied in main plots and different wheat varieties were grown in sub-plots. The seeds were sown on December 05, 2012 and November 30, 2013 for the growing season of 2012-13 and 2013-14, respectively. The wheat varieties used in this study were Shatabdi, Sufi, Sourav, Bijoy, Prodip, BARI GOM 25 and BARI GOM 26. The index of relative performance of each variety in comparison to mean yield of all varieties under the contrast conditions of liming and non-liming was estimated to determine relative adaptability of wheat variety under experimental soil conditions. The result indicated that most of the yield components viz. spikes/m2, thousand grain weight and grain yield of wheat were significantly improved by liming for both the years and locations. There were variations in lime response among the wheat varieties. The index of relative adaptability (IRA%) for yield of BARI GOM 26 and Bijoy was more than 100% for both the years. The result indicated that these two wheat varieties are relatively tolerant to low pH and could be adapted in acidic soil of Sylhet.