International Maize and Wheat Improvement Center (CIMMYT), P.K. 39 Emek 06511 Ankara, Turkey
Nilufer,Akci, Sridhar, Bhavani, Mesut, Keser, Fatih, Ozdemir, Ruth, Wanyera, Alexey, Morgounov, , , , , , , , , , , , , , , , , ,
A diverse set of winter wheat germplasm was screened for resistance to stem rust in large-scale trials in Kenya and Turkey during 2009-16. The study aimed to select resistant material and characterize types of resistance and possible genes, as well as evaluate agronomic traits and resistance to other diseases to select superior variety candidates and parental lines. The study material was comprised of various Facultative and Winter Wheat Observation Nurseries (FAWWON), which are developed and distributed by the International Winter Wheat Improvement Program (www.iwwip.org) in Turkey. More than 1600 global accessions were screened, with most evaluated for two years. Based on stem rust data from Kenya, more than 400 genotypes were identified exhibiting adequate levels of resistance to the Ug99 race group. The highest number of resistant lines originated from IWWIP (~170), USA (~100), Russia (~40), Iran (~30), Romania (~20), and South Africa (~20). Material was also tested at two sites in Turkey: Haymana (artificial inoculation) and Kastamonu (natural infection). There was no significant correlation between stem rust severities in Kenya and in Turkey, due to differences in stem rust pathotypes. However, a set of germplasm (more than 100 entries) has been identified as resistant in both countries. This set represents promising material as variety candidates and parental lines; another study is currently identifying the genes controlling the stem rust resistance in this population. IWWIP distributed stem rust resistant germplasm to its global collaborators during 2010-2015, in response to the threat from the Ug99 race group. New resistant germplasm combining broad adaptation, high yields, and resistance to other diseases is available on request.
Seed and Plant Improvement Institute, Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
The basidiomycetous fungus, Puccinia graminis f. sp. tritici (Pgt) causes stem rust disease as one of the most destructive wheat pathogens, worldwide. TTKSK and other Pgt races under Ug99 race group are considered as major threats to wheat production in east Africa and CWANA region by defeating the stem rust resistance gene Sr31, while its ineffectiveness was reported in Iran in 2007. Race TKTTF of Pgt caused a severe stem rust epidemic in southern Ethiopia in 2013, and was spread to Europe through 2016 Sicily outbreak. This research describes race identification of Iranian isolates collected during the widespread distribution of stem rust in 2014-16. Purified urediniospores of 123 Pgt isolates were separately inoculated on seedlings of 20 North American differential wheat cultivars carrying different Sr resistance gene/s. Infection types were recorded at 14 days post inoculation (dpi) using Stakman et al. 0-4 scale. Based on the letter code nomenclature, we identified the Pgt races TKTTF, TTTTF, TTKSK, TTKTK, PKTTF, TKSTF, PKSTF, PKTTC, PTRTF, PTTTF, PKSTC, TTRTF, TKSTC and PKRTF in Iran. TKTTF and TTTTF were determined as prevalent Iranian Pgt races. This is the first report of race TTKTK, a new variant of Ug99 race group with virulence on Sr31 and SrTmp resistance genes, in Iran. Since TTKTK primarily occurred in south west of Iran, the migration route for this new race seems to be similar to race TTKSK. The high race variation observed in this study could indicate a high genetic diversity among P. graminis f. sp. tritici populations in Iran, as a wheat center of origin.
Kenya Agricultural and Livestock Research Organization
Hanningtone,Wanga, Phelister, Kinyanjui, Sridhar, Bhavani, Thomas, Fetch, , , , , , , , , , , , , , , , , , , , , ,
In 2016 rust surveys were carried out in all the four key wheat growing regions: South Rift (June, July), Mount Kenya (July), North Rift (September) and Central Rift (part of August and September). A total of 304 farms were sampled. Stem rust was detected in 235 (78.3%), yellow rust in twenty-eight (9.3%) and leaf rust in fourteen (4.7%) of the farms. Stem and yellow rust were detected in all the wheat growing regions while leaf rust was detected in South, North and Central Rift. Stem rust infection ranged from TR to 90S with maximum infection in Central Rift (88.3%), Mt. Kenya region (80.3%); South Rift (76.5%) and North Rift (72.4%). Yellow rust infection ranged TR to 60S with maximum infection in Central Rift (16.7%); North Rift(13.3 %) and minimum infection in South Rift( 4.9%),) and Mt. Kenya region ( 1.7%). Leaf rust infection ranged from trace to 50S with maximum infection in North Rift (10.2%) minimum infection in Central Rift (3.3 %) and South Rift (1.2%). Fifty percent of the eight previously released wheat varieties are now susceptible to the Ug99 race. Race analysis results from AAFC Canada suggested the presence of TTKSK which was dominating in North Rift and TTKSK, TTKST and TTTTF were dominant in the screening nursery at Njoro. Yellow rust in the region has increased in the current year owing to the incursion of a probable new race AF2012 which has resulted in increased disease severity on varieties and materials tested in the International nurseries at KALRO, Njoro.
Crop Diseases Research Institute, PARC Substation, Murree Pakistan
Sufyan,Muhammad, Abid Majeed, Satti, Munir, Anjum, Fayyaz, Muhammad, Atiq ur Rehman, Rattu, Imtiaz, Muhammad, , , , , , , , , , , , , , , , , ,
225 Puccinia striiformis f.sp. tritici isolates collected from wheat growing areas of Pakistan during 2013-2016 were analyzed using 18 near isogenic yellow rust differentials. Seventy eight races were identified among collection in which 20 were common (n > 2). Rest of the races were very rare and encountered only once (n=1). Races 574212, 574232, 474232, 474233, 574213 and 434232 were most frequent (n> 15). Pathogenic diversity analysis of the collection reveal high diversity (H =3.57) of the P. striiformis population of pakistan. On the basis of phenotypic response to yellow rust genes, the most frequent races could be grouped into 5 diverse groups. Distinct grouping was also observed in rarely encountered isolates. Most of the races were highly complex and 80% isolates had complexity ranging from 8 to 11. Virulence frequency for Yr6, Yr7, Yr8, Yr17, Yr27, Yr43 & YrExp2 remained above 80% while that of Yr1, Yr9 and Yr44 remained over 40%. Partial virulence was detected for Yr5, while virulence to Yr10, Yr15, YrSP was found in < 4% isolates. Paper discuss spatial and temporal distribution of P. striiformis races in Pakistan.
Michel E. Ghanem, Sarrah Ben M'Barek, Gustavo Azzimonti, Silvia Pereyra, Silvia Germán, Felix Marza, Amor Yahyaoui, Pawan Singh, Michael Baum, Hans-Joachim Braun
Based on a global network of wheat partners, precision field-based wheat phenotyping platforms are being developed with the support of the CGIAR Research Program on Wheat and co-investing national agricultural research institutes. This collaboration strategy aims to i) strengthen the quality of phenotypic data to fully exploit the potential of genomic data, ii) strategic prioritization of activities based on trait screening capacities and regional needs, iii) sharing knowledge and germplasm to accelerate superior germplasm development and dissemination, iv) development of capacities. Phenotyping activities are being conducted for wheat blast (Magnaporthe oryzae) in Bolivia, Septoria tritici blotch (STB) in durum wheat in Tunisia, and for multiple diseases (leaf rust, Fusarium head blight, and STB) in bread wheats in Uruguay. Subject to further funding, additional platforms will be implemented, to contribute to a faster development of broad genetic based resistant, high yielding wheat varieties, and complementing evaluations currently performed for diseases and heat, drought and yield potential (Kenya, Ethiopia, Turkey, Mexico).
Ravi Singh, Karim Ammar
Stripe rust, caused by Puccinia striiformis tritici (Pst), continues its evolution towards virulence to race-specific resistance genes. Identification of Mexican Pst isolates MEX16-03 and MEX16.04 that changed infection types of Yr10 testers from 1 to 9 and for Yr24 (=Yr26) testers from 3 to 9 indicated that a mutation for virulence to these resistance genes has occurred in a predominant race detected in 2014 and maintained at CIMMYT as MEX14.191 and at INIFAP as CMEX14.25. Isolate MEX14.191 was responsible for the susceptibility of popular varieties Nana F2007 and Luminaria F2014 grown in central Mexican highlands. Isolate MEX16.04 has the following avirulence/virulence formula: Yr1, 5, 15, SP/Yr2, 3, 6, 7, 8, 9, 10, (17), 24, 26, 27, 28, 31, 32 using the Avocet near-isolines and other known testers. Virulence to Yr10 and Yr24 (=Yr26) were also confirmed by testing seedlings of cultivars Moro (Yr10), Chuanmai 42, and Neimai 836 (Yr24). Seedling tests carried on 200 bread wheat, 550 durum, and 460 synthetic hexaploid wheats with their respective durum parents from CIMMYT collection indicated that MEX16.03 and MEX16.04 do not represent a major threat because a majority of the lines remained resistant to these isolates. However, it is worth mentioning that durum cultivars, such as Khofa, Desert King, Anatoly, Movas, and Llareta INIA, and 10 primary synthetic hexaploid or synthetic-derived bread wheats that were resistant to MEX14.191 became susceptible to MEX16.03 and MEX16.04. Our results indicate that resistance gene Yr10 was absent and Yr24 occurred in low frequency in CIMMYT bread wheat germplasm. A majority of CIMMYT durum wheat possibly carried Yr24 in combination with other effective gene(s).
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.
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%).
Vegetable Research Institute AARI, Faisalabad, Pakistan.
Etlas,Amin, , , , , , , , , , , , , , , , , , , , , , , , , , , ,
In the present study five bread wheat genotypes (9797, 9801, 9802, Chakwal-50 and Chakwal-86) were tested in a 5?5 full diallel analysis for the estimation of combining ability for yield and its related traits. In randomized complete block design (RCBD) twenty F1s along with their parents were planted in field with three replications in the research area of Department of Plant Breeding and Genetics, University of Agriculture, during 2014-15. Plant height, No. of grains/spike, spike length, No. of productive tillers/plant, flag leaf area, No. of spikelets/spike, 1000 grain weight and grain yield per plant were studied. Except spike length mean squares due to GCA were highly significant for all the traits. All the characters showed highly significant mean squares for SCA and RCA. SCA variance was lower than GCA variance for number of grains/spike and spike length presenting the major role of additive gene action in the inheritance of these traits. While for plant height, flag leaf area, number of spikelets/spike, number of fertile tillers/plant, 1000 grain weight and grain yield/plant the value of GCA variance was lower than the value of SCA variance exhibiting non-additive gene action. Chakwal-50 was the best general combiner for plant height, spike length, number of spikelets/spike, number of grains/spike and grain yield/plant. The best specific combination for most of the traits was 9802?Chakwal-86. In future wheat breeding research programmes, good specific and general combiners can be exploited.
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.