All BGRI Abstracts

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Aecial infection status of Berberis spp. in Kastamonu province of Turkey

BGRI 2018 Poster Abstract
Nil?fer Akci Central Research Institute for Field Crops, Yenimahalle, Ankara, Turkey
Aziz Karakaya

Berberis species are important alternate hosts and generate new races of stem rust fungus, Puccinia graminis f. sp. tritici and yellow (stripe) rust fungus Puccinia striiformis. Berberis species are common in Kastamonu province of Turkey. In 2016 and 2017, surveys were conducted in Kastamonu province in order to elucidate aecial infection status of Berberis species in this region. In 2016, the central region and A?l?, Ara?, Daday, ?hsangazi, Seydiler, Ta?k?pr? and Tosya regions and in 2017 central region and Ara?, Daday, Han?n?, P?narba??, Seydiler, Ta?k?pr? and Tosya regions of Kastamonu province were investigated. It appears that there are at least two different Berberis species exist in that area. Berberis species showed variation in terms of fruit color and morphological characters. In 2016, 50 Berberis plants were examined and aecia were present in 38 plants (76%). Percentage of plants parts infected with aecia ranged between 3-80%. In 2017, 64 Berberis plants were examined. Aecia were present in 34 plants (53%). Percentage of plants parts infected with aecia ranged between 3-85%. Aecia were mainly observed on leaves but also observed on other plant parts including flower parts, fruit and young twigs. The role of these aecia and Berberis spp. on rust diseases in Kastamonu province of Turkey should be investigated.

This study was supported by General Directorate of Agricultural Research and Policies, Turkey (Project No: TAGEM-BS-15\12-01\02-02).

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Existence of divergent lineages, virulence phenotypes and DNA methylation in the Canadian Puccinia striiformis population

BGRI 2018 Poster Abstract
Gurcharn Singh Brar 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.

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Triticum araraticum: A source of leaf rust and stripe rust resistance genes

BGRI 2018 Poster Abstract
Rohtas Singh School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana-141004 India
Ahmed Elkot, Satinder Kaur, Parveen Chhuneja

Stripe rust and leaf rust are two most widely distributed diseases of wheat despite the fact that major emphasis has been made globally to develop rust resistant varieties. The wild tetraploid wheat Triticum araraticum (AAGG) evolved in the eastern part of Fertile Crescent is a source of useful traits for the improvement of wheat including resistance to disease. T. araraticum acc. pau4692 and a derived advanced backcross introgression line (IL) in susceptible T. durum cv. Malvi local background showed high level of seedling resistance against Indian pathotypes of leaf rust and stripe rust. The F5 Single seed descent (SSD) population developed from the crosses between T. araraticum IL with T. durum cultivar PBW114 was screened with commonly prevalent pathotypes of leaf rust and stripe rust in India at the seedling stage. The genetic analysis indicated that the leaf rust resistance is conditioned by two genes and stripe rust resistance by a single gene. The SSR markers mapped on A and B genome were used for parental polymorphism along with resistant and susceptible bulks for leaf rust and polymorphic markers between bulks were used on the whole population. The molecular marker data using single marker analysis showed that leaf rust resistance genes were mapped on chromosome 2A and 7A linked to SSR markers Xwmc149 and Xbarc49, respectively. The genes have been temporarily named as LrAr1 and LrAr2. Bulked segregant analysis (BSA) for mapping stripe rust resistance is in progress.

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Breeding of high yielding, rusts resistance and Zn-enriched wheat varieties for different agro-ecological zones of Pakistan

BGRI 2018 Poster Abstract
Maqsood Qamar 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.

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New QTL for leaf rust and stripe rust resistance in four bread wheat and two durum wheat mapping populations

BGRI 2018 Poster Abstract
Caixia Lan CIMMYT
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.

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Speed breeding with genomic selection to accelerate genetic gain for yield in spring wheat (Triticum aestivum)

BGRI 2018 Poster Abstract
Amy Watson University of Queensland

Genomic selection (GS) in wheat can accelerate yield gain principally through a reduction in breeding cycle duration. A method for rapid generation advance called ?speed breeding? (SB) enables up to six generations of spring wheat per year, and could be used to accelerate breeding population development and be combined with GS in various breeding schemes to enable even further gains. SB and GS could be combined through a variety of different scenarios using single seed descent and also by applying GS to segregating populations in the glasshouse. Selected lines could then go into multi-location field trials for final selections and to obtain information for updating the prediction model. The increase in speed in these scenarios compared with field-based breeding schemes could greatly improve genetic gain for valuable target traits, such as yield. To test these hypotheses, a 260 multi-parent spring wheat population, genotyped with 8,000 DArT polymorphic markers, underwent yield trials over three years. Yield prediction accuracy was accessed using five-fold cross validation and predicting across years. Using these results, the rate of genetic gain achieved through either phenotypic selection in the field or a combination of SB and GS in the glasshouse were calculated. Results indicate that incorporating GS into SB growing systems would result in a higher rate of genetic gain compared to phenotypic or more traditional GS breeding schemes, due to the greater number of generations produced per year. This approach may be able to be coupled with multi-trait GS prediction models to increase accuracy, advance genetic gain and wheat variety development.

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Accelerated Cloning and Characterization of Adult Plant Resistance Genes in Wheat

BGRI 2018 Poster Abstract
Sreya Ghosh 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.

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Assessment of slow rusting of landraces of bread wheat to Puccinia striiformis f.sp. tritici under artificial field inoculation

BGRI 2018 Poster Abstract
Fedaa Alo ICARDA

Yellow rust caused by Puccinia striiformis f.sp. tritici, is the most devastating fungal disease of wheat, especially in CWANA region. Growing cultivars with durable resistance is the most economical control measure. A field study was conducted to evaluate 500 bread wheat landraces along with the susceptible control ?Morocco? using artificial inoculation under field conditions at Tel Hadia, Syria during 2010-11 and 2011-12 growing seasons. The most prevailing yellow rust virulent race 70E214 was used for artificial inoculation. The disease scoring started when the disease severity was more than 50 % on the leaves of the susceptible check ?Morocco? and continued for four scorings at the intervals of 7 days. Slow rusting resistance was assessed based on the development of disease over time using the Area under Disease Progress Curve (AUDPC), Coefficient of Infection (CI), Final rust Severity (FRS), Infection Rate ?(r)? and Relative Resistance Index (RRI). None of the landraces showed immune reaction and 10% showed lowest values for all parameters, suggesting that resistance in these landraces was controlled by major genes. Approximately 65% of landraces were marked as having different levels of slow rusting and 25% were highly susceptible. Cluster analysis based on partial resistance parameters revealed two major clusters: Susceptible and low level of slow rusting were grouped in the first cluster; Resistant, high level and moderate level of partial resistance were grouped in the second cluster. By comparing the results obtained from RRI and others parameters, we found that landraces with very low values for all parameters exhibited high RRI value of 9, while those that showed high, moderate and low levels of slow rusting, had RRI ranges of 8-9, 7-8 and 5-7, respectively. The landraces with maximum values from each parameter showed very low RRI values of less than 5.

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Harnessing the predictive power of epidemiological modelling for wheat yellow rust disease

BGRI 2018 Poster Abstract
Vanessa Bueno-Sancho 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.

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Large scale pre-breeding efforts for broadening gene pool and genetic improvement of wheat

BGRI 2018 Poster Abstract
Sukhwinder Singh CIMMYT
Prashant,Vikram, Deepmala, Sehgal, Juan, Burgueno, Carolina, Sansaloni, Cynthia, Ortiz, Ernesto, Solis, Lulu, Ledesma, Pillar, Suaste, G, Fuentes, J, Ireta, A, Sharma, P, Srivastava, Sridhar, Bhavani, Thomas, Payne, V, Govindan

Wheat breeding programs have successfully harnessed the potential of elite germplasm pool and have contributed significantly to global food security. However, to obtain additional genetic gain, useful diversity for key traits from landraces, synthetics and wild relatives should be incorporated in breeding germplasm pool. Maladaptation and linkage drags are the bottlenecks in utilizing these exotic genepools for pre-breeding. A systematic, focused, large scale effort has been pursued at CIMMYT through a three-way cross (exotic x elite1 x elite2) population development strategy. Population was advanced through selected-bulk scheme in way to select relevant genetic diversity while maintaining large population sizes. A total of 984 advanced pre-breeding lines (PBLs) were evaluated in multiple environments for grain yield related traits, micronutrient content and diseases resistance (yellow rust, stem rust, powdery mildew, and karnal bunt). Potential useful lines for these traits have been identified. High-density genomic characterization of PBLs, parental elites and exotics was conducted through a "haplotype map" based approach, which revealed 16% (58/361) exotic specific haplotype block (HB) introgression in PBLs. Out of 58 exotic specific HBs, 12 (12/361 = 3%) were found associated with traits evaluated in the study. Three HBs, H1.28 (1A), H18.1 (6D) and H5.23 (2B) were significantly important as they showed consistent effects across environments for grain yield (1A and 6D) and yellow rust (2B). This significant contribution of exotics into PBLs opens avenues to mine and utilize their useful alleles in wheat improvement. This research describes systematic large-scale pre-breeding efforts, as proof of concept of exotic germplasm deployment to the breeding pipelines simultaneously enriching genetic knowledge through high-density genomics analysis. Genetic knowledge coupled with breeding efforts should provide substantial gain required for next generation wheat varietal improvement.

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