ICAR Indian Institute of Wheat and Barley Research, Karnal
Satish Kumar, Rekha Malik, Garima Singhroha, Vinod Tiwari, Gyanendra Pratap Singh
Breeding rust resistant cultivars using conventional methods is time-consuming, complex and slow, but molecular markers offer a rapid alternative for developing cultivars with improved disease resistance. Three wheat cultivars, DBW88, DBW107, and DBW110, from different production zones were used as recipients for incorporation of resistance genes using a marker-assisted backcross (MAB) breeding approach. Leaf rust resistance gene Lr32 is being incorporated into all the three varieties, stripe rust resistance gene Yr15 is being incorporated into DBW88 and DBW107, and stem rust resistance gene Sr26 is being added to variety DBW110. Lines PBW703 (Yr15), FLW15 (Lr32) and Avocet (Sr26) were used as donors. Six cross combinations viz., DBW88/PBW703, DBW107/PBW703, DBW88/FLW15, DBW107/FLW15, DBW110/FLW15 and DBW110/Sr26 were made at Karnal during 2015-16 and the crosses were grown at IIWBR-RS, Dalang Maidan for backcrossing. BC1F1 plants were raised at Karnal during 2016-17. Both foreground and background selections were practiced in each combination. SSR markers gwm264 and barc135 were used for foreground selection of Lr32, marker barc8 was used for selection of Yr15, and markers Sr26#43 and BE518379 were used to detect presence and absence of Sr26. From 90 to 127 polymorphic SSR markers chosen for each cross from an initial set of 800 screened on the parents are being used for background selection.
Department of Field Crops, Ege University, Izmir, Turkey
Kumarse Nazari, Mehran Patpour, Davinder Singh, Aladdin Hamwieh
Rust diseases in wheat are the major threat to wheat production and yield gains. The breakdown in resistance of certain major genes and new emerging aggressive races of rusts are causing serious concerns in all main wheat growing areas of the world. Therefore, it is the need of the hour to search for new sources of resistance genes or QTL's for effective utilization in future breeding programs. In total 100 wheat genotypes were evaluated for seedling and adult-plant resistance to stem rust races TKTTF and TTKSK at Tel Hadya-Syria, and Njoro-Kenya, and Kelardasht-Iran. Evaluation to Yr27 virulent stripe rust race was carried out at Tel Hadya and Terbol-Lebanon research stations. In this study we used genome wide association studies (GWAS) to identify markers or QTLs linked to stem rust and stripe rust races using Diversity Arrays Technology (DArT?) in selected 35 Iranian wheat genotypes. The association of markers and phenotypes was carried out using a unified mixed-model approach (MLM) as implemented in the genome association and prediction integrated tool (GAPIT). Out of 3,072 markers, 986 were polymorphic and used for marker trait associations. A total of 44 DArT markers were identified to be significantly (p<=0.01) associated with studied traits in 16 genomic regions 1A, 1B, 2A, 4A, 6A, 7A, 1B.1R, 2B, 3B, 4B, 5B, 5B.7B, 6B, 7D and an unknown region. Among associated markers, 34 were linked to stem and nine to stripe rust. They were found on 16 genomic regions on chromosome arms 1A, 1B, 2A, 4A, 6A, 7A, 1B.1R, 2B, 3B, 4B, 5B, 5B.7B, 6B, 7D and an unknown region. Associated markers explained phenotypic variation ranging from 21 to 65%. In addition to validation of previously identified genes, this study revealed new QTL's linked to stem and stripe rust which will assist breeders to develop new resistant varieties.
Ethiopian Institute of Agricultural Research
Bedada Girma, Endale Hailu, Fikrte Yirga, Bekele Abeyo, Gordon Cisar, Gina Brown-Guedira, Erena Edae, Pablo Olivera, Matthew Rouse
In Ethiopia, breeding resistant wheat varieties is a priority for wheat rust management although new virulent rust races have periodically resulted in losses of R-genes, epidemic outbreaks, and yield losses of up to 100%. During 2014 and 2015, 160 wheat varieties and lines including five checks and 12 differential lines with known resistance genes were evaluated against four stem rust pathogen races at both seedling and adult plant stages. In the field at Kulumsa, Ethiopia, the lines were evaluated in four separate nurseries in an augmented design where each nursery was inoculated with a different Puccinia graminis f. sp. tritici race: TTKSK, TKTTF, TRTTF, and JRCQC. Kingbird, a check variety, displayed low average Area Under the Disease Progress Curve (AUDPC) (67 to 238) and Average Coefficient of Infection (ACI) (1.1 to 9.7) in response to the four races. Effect of lines possessing Sr24+Sr36 and Sr31+Sr36 resistance genes on rust development was comparable to Kingbird or even better. Likewise, 48, 34, 19 and 28 varieties and lines had lower or comparable AUDPC for TTKSK, TKTTF, TRTTF and JRCQC compared to Kingbird. Commercial bread wheat varieties Shorima, Huluka, Hogana, and advanced lines CIMMYT 14, ETBW7058, ETBW7101 and ETBW7258 for which Sr24/Lr24 was postulated, possessed AUDPC and ACI lower than Kingbird. However, all these lines possessed susceptible or intermediate seedling reactions to Sr24-virulent race TTKTT from Kenya at the seedling stage. CIMMYT 18 showed susceptibility to 3 races at seedling stage, but lower AUDPC and ACI than the checks except Kingbird, indicating adult plant resistance. However, this adult plant resistance was marginal in effect to race TKTTF. Resistance genes Sr2, Sr57/Lr34, Sr24/Lr24, Sr25/Lr19, Sr38/Lr37 and SrTmp were postulated at various frequencies in this germplasm. Seedling and adult plant resistance sources identified can be used for rust resistance breeding in Ethiopia.
Cereal Crops Research Institute Pirsabak Nowshera, Pakistan
Khilwat Afridi, Muhammad Ishaq, Irfan Shah, Ibne Khalil, Masood Jan
The Cereal Crops Research Institute (CCRI) is situated on the left bank of River Kabul, near village Pirsabak, 3 km east of Nowshera at an elevation of 288 m above sea level on the intersection of 74? E longitude and 32? N latitude. In July 2010, a devastating flood destroyed all the available germplasm, machineries, laboratories, and field equipment. After the flood research activities were restarted with full motivation, dedication and hard work in collaboration with PARC, ICARDA, CIMMYT, and with the help of wheat productivity enhancement program (WPEP). Developed new population of wheat via spring x spring, spring x facultative germplasm to elevate genetic diversity and lines selected from segregating populations for high yield and rust resistance are at advanced stage of testing.
Since the flood, the CCRI developed four new wheat cultivars: Pirsabak-2013 Pakhtunkhwa-2015 for irrigated areas and Shahkar-2013 and Pirsabak-2015 for rainfed areas of Khyber Pakhtunkhwa, Pakistan. Varietal maintenance and seed production of the released varieties has been undertaken by the wheat breeding team effectively. The seed of these newly developed wheat cultivars was multiplied on fast track basis through pre-released seed multiplication and now these four varieties are the most popular cultivars of Khyber Pakhtunkhwa, Pakistan. Three new candidate wheat lines (PR-106, PR-110 and PR-112) have been submitted to provincial seed council for approval as new wheat cultivars for Khyber Pakhtunkhwa, Pakistan. Two new candidate lines i.e. PR-115 and PR-118 got first position in National Uniform Wheat Yield Trials (NUWYT) on the basis of grain yield during 2016-17 under irrigated and rainfed conditions, respectively.
Maize Research Institute Zemun Polje
Dragana Ranćić, Vesna Kandić, Biljana Vucelić-Radović, Jasna, Savić, Miroslav Zorć
When environmental stress develops during reproductive phases of growth, wheat plants have to rely increasingly on remobilisation of previously stored assimilates to maintain grain filling. The present study was undertaken to determine the effect of several peduncle (the uppermost stem internode) morpho-anatomical and biochemical traits on grain weight, and to assess the contribution of the peduncle water-soluble carbohydrate (WSC) reserves shortly after anthesis to its variation. In 2-year field trials, 61 wheat genotypes were used (27 F4:5 families, 17 parents used for the crosses and the 17 current best standards) comparing intact control plants (CP) with plants that were defoliated (DP) by cutting off all leaf blades 10 days after anthesis to simulate terminal stress. Estimated contributions of peduncle assimilate reserves to grain weight/spike were from 0.06 to 0.31% and from 0.11 to 0.45% in CP and DP plants, respectively. High peduncle reserve mobilization efficiency, a longer exposed part of the peduncle and larger peduncle storage capacity (through higher parenchyma and/or lower lignified area) were of specific benefit for maintaining grain weight in defoliated plants. There was a large difference in compensation of grain yield loss by dry matter remobilization within studied genotypes (in average 1.2-36.1%). Although compensation of yield loss might be improved through breeding process (our F4:5 families had slightly higher mean compensation effect than their parents under moderate stress), it does not mitigate the effect of post-anthesis drought in great extent (up to 38.4%).
QAAFI, The University of Queensland
Robert McIntosh, Peng Zhang, Sami Hoxha, Adnan Riaz, Burkhard Steuernagel, Brande Wulff, Evans Lagudah, Lee Hickey, Sambasivam Periyannan
Wheat is one of the most important staple food and agricultural crop cultivated worldwide. To meet the demands of the raising human population, global wheat production has to be increased which is however declined due to appearance of highly virulent strains of Puccinia striiformis f. sp. tritici (Pst) fungus causing stripe rust disease. Globally, the incidence of stripe rust is effectively managed through the deployment of host plant mediated genetic resistance. But as the resistance present in the current wheat cultivars are ineffective, new sources of resistance particularly from pathogen unexposed genetic resources are of urgent need to prevent stripe rust epidemics. Landrace collections with rich genetic diversity and being less exposed to prevalent pathogen are of valuable source for resistance to new pathogens. In this study, a total of 295 landrace accessions collected by the famous Russian botanist Vavilov was screened for stripe rust resistance using the two predominant lineage Pst strains of Australia. Six accessions with good resistance against the two aggressive Pst strains were selected for genetic characterization and for utilization in global wheat breeding. Characterisation of these novel resistance were undertaken using combination of conventional and advanced genetic tools. While the conventional approach involves the traditional map based gene cloning, the other tool is the recently identified rapid method based on mutagenesis, targeted gene capture and next generation sequencing called "MutRenSeq". Subsequently, the identified novel resistant traits were transferred into elite wheat cultivars through the combination of linked molecular markers and speed breeding techniques. Thus along with the identification of novel resistance, elite wheat cultivars with broad spectrum stripe rust resistance were also generated through the use state of art techniques to sustain global wheat production from the rapidly evolving stripe pathogens.
Faculty of Agriculture, The University of Jordan
Moneer Mansour, Nasab Rawashdah, Rabei Sayaydeh
Durum wheat (Triticum turgidum subsp. durum) landraces are rapidly disappearing from the main wheat production areas in the Fertile Crescent. Such local landraces are most likely contain geographically specific, ectopically adapted alleles or gene complexes for their harsh environments. A panel of 156 durum wheat landraces and released varieties were assembled from historical collections deposited in national and international gene banks and from a recent active collection mission from selected areas across Jordan. The panel were evaluated under field conditions in two different locations for one growing season. Data for days to heading, plant height, peduncle length, number of spikes spike length, spike weight, grains number, grains weight, number of kernels per spike and thousand-kernel weight were recorded. Results indicate the existence of a wide variation between the tested genotypes for all tested agronomical traits. For heading date, the Jordanian landrace "JDu103" was the earliest under dry environment conditions. Regarding grains weight and spike weight, the Jordanian landrace "JDu105" produced the highest mean value under humid conditions. Another landrace "JDu46" produced the longest spikes and the highest TKW mean value, while the Jordanian landrace "JDu105" produced the heaviest spikes weight mean value, while "JDu100" produced the highest grains number. For molecular analysis, total genomic DNA was extracted from each genotype and then used for SNP genotyping using Illumina iSelect wheat 90k SNP chip. Structure analysis showed that the analyzed durum wheat panel can be divided into three genetically distinct subgroups. The GWAS analysis identified 93 significant markers-traits associations for multiple traits with two QTLs located at 7A and 7B, which seems important for TKW in durum wheat under dry environments. In conclusion, the Jordanian landraces used in this study showed wide genotypic and phenotypic variability, which can be considered by plant breeders for their future use in breeding programs.
Rosemary,Shrestha, Kate, Dreher, Victor, Jun Ulat, Luis A., Pubela Luna, Susanne, Dresigacker, , , , , , , , , , , , , , , , , , , ,
The Global Wheat Program of CIMMYT is one of the largest public breeding programs in the world consisting of millions of lines/ genotypes derived from thousands of crosses evaluated under using a shuttle breeding cycle and multi-environment testing. The germplasm is phenotyped for conventional (such as yield and grain quality) as well as non-conventional traits (physiological traits) in field and greenhouse conditions. The breeding germplasm is also screened with genome-wide markers (using Illumina SNP array, genotyping-by-sequencing, or DArTseq platforms) and/or multiple gene/QTL region-specific molecular markers (using KASP platform). All genotyped samples are registered in the "DNA SampleTracker," a software system for tracking DNA samples developed at CIMMYT. In collaboration with High Throughput Genotyping Platform project, the plant sample and data collection methods are optimized. Meanwhile, the extensive wheat genealogies and phenotypic information have been maintained in the International Wheat Information System and will be transferred to a new Enterprise Breeding System. Furthermore, several bioinformatics/statistical genetics methods with the objectives of gene discovery and genomic prediction have been developed and utilized for optimizing genomics-assisted selection. The wheat team is a member of "Genomic Open-source Breeding Informatics Initiative (GOBII)" which aims to develop and implement genomic data management systems to enhance the capacity of breeding programs. Under this initiative, a new genomics database has been built and a pilot wheat version is being tested at CIMMYT. Several decision support tools are also under collaborative development, such as a Genomic Selection Pipeline based on Galaxy, Flapjack-based F1/line verification, and marker assisted backcrossing tools. Additional tools are envisioned for the future including a Cross-Assistor and Selection-Assistor. The ultimate aim is to seamlessly connect the genomic database, phenotypic database, and decision support tools to support the breeding selection process and to lead to the development of cultivars with increased rates of genetic gain.
Institute of Agricultural Sciences, Banaras Hindu University, India-221005
Punam Singh,Yadav, Naveen Kumar, Umesh Chandra, Dubey, Ramesh Chand, Sundeep Kumar, Arun Kumar Joshi
Four leaf rust adult plant resistance genes (Lr34, Lr46, Lr67 and Lr68) are known to be associated with leaf tip necrosis (LTN). LTN caused by these genes is different from each other at phenotypic level. LTN associated with APR genes Lr34, Lr46 and Lr67 has been designated as Ltn1, Ltn2 and Ltn3. Seventy-seven CIMMYT genotypes were selected to find out the association between genotypic and phenotypic variability for LTN and its association with yield traits; 1000 grain weight, grain yield, leaf area and percentage of leaf tip necrosis in the flag leaf of main tiller. All the genotypes were screened for the presence of 3 APR genes with linked markers, csLV34 for Lr34; Xwmc44 and Xgwm259 for Lr46 and Xcfd71 for Lr67. The genotypes were grouped into 5 classes; only Lr34, only Lr46, only Lr67, Lr34+L46+Lr67 and genotypes lacking all three genes. Molecular analysis revealed that 7 genotype with Lr34 only, 6 with Lr46 only, 7 with Lr67 only, 13 with all the 3 genes, and 28 without any Lr gene. Phenotypic data of LTN percentage was compared and it was noted that maximum LTN % was observed for Lr67 (7.811%) followed by Lr46 (7.348%) and Lr34 (6.47%). Surprisingly, presence of all three genes reduced the LTN% (4.7055%) as compared with absence of all three genes (6.011%). It was also observed that the three genes simultaneously reduced 1000 grain weight and plot yield. All three genes increased leaf area highly significantly both when they are alone or together (34.7 to 44.7 cm2) in comparison to those genotypes (24.7 cm2) which lacks these Lr genes and also reduced 1000-grain weight and plot yield but non-significantly.
Jamal El Haddoury, Ahmed Amri
Malika', a hard red spring wheat (Triticum aestivum L.) cultivar developed using doubled haploid technology by the Institut National de la Recherche Agronomique (INRA), Morocco, and tested as 06DHBW48, was approved for release in 2016 by the Office National de S?curit? Sanitaire des Produits Alimentaires (ONSSA), Morocco. Malika was selected from the doubled haploids derived from the cross 'Achtar3*//'Kanz'/Ks85-8-4). Achtar and Kanz are Moroccan varieties originating from segregating populations from CIMMYT. Achtar and Kanz are a well adapted to Moroccan conditions but susceptible to the Hessian fly, yellow rusts and some races of leaf rust. 'Achtar' was crossed with it in order to incorporate the Hessian fly resistance, yellow rust resistance and leaf rust resistance and 'Achtar' was crossed with Kanz/Ks85-8-4 having resistance to Hessian fly, yellow rust and leaf rust. Backcrossed 3 times with 'Achtar', and selected lines having resistance to the Hessian fly, yellow rust and leaf rust from the population derived from each backcross. Finally the selected the resistant line was used develop doubled haploids. The doubled haploid lines produced were tested in the laboratory and field for Hessian fly and the rust resistance. The resistant lines were incorporated in the multi-local yield trials and three promising lines with the resistance to Hessian fly, yellow rust and leaf rust and better yield and quality were submitted for registration in the official catalog in 2014. After 2 years of testing (years 2014-15 and 2015-16), one line (06DHBW48) was accepted for the registration and designated as 'Malika'. 'Malika' is a semi-dwarf variety, well adapted to semi-arid regions, early maturing, high yielding, tolerant to drought and resistant to Hessian fly, leaf rust and yellow rust.