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.
University of Minnesota
Michael Pumphrey, Matthew Rouse
Stem rust of wheat caused by the fungal pathogen Puccinia graminis f. sp. tritici historically caused major yield losses of wheat worldwide. To understand the genetic basis of stem rust resistance in contemporary North American spring wheat, genome-wide association analysis was conducted on 250 elite lines. The lines were evaluated in separate nurseries each inoculated with a different P. graminis f. sp. tritici race for three years (2013, 2015 and 2016) at Rosemount, Minnesota. The lines were also challenged with the same four races at the seedling stage in a greenhouse facility at the USDA-ARS Cereal Disease Laboratory. A total of 22,310 high-quality SNPs obtained from the Infinium 90,000 SNPs chip were used to perform association analysis. Markers strongly associated with resistance to the four races at seedling and field environments were identified. At the seedling stage, the most significant marker-trait associations were detected in the regions of known major genes (Sr6, Sr7a and Sr9b) except for race QFCSC where a strong association was detected on chromosome arm 1AL. Markers presumably linked to Sr6 and Sr7a were associated with both seedling and field resistance to specific races. A field resistance QTL on chromosome arm 2DS was detected for response to races RCRSC and TPMKC. A QTL specific to field resistance was detected for QFCSC and TPMKC on 2BL. The markers that showed strong association signals may be useful to pyramid and track race-specific stem rust resistance genes in wheat breeding programs. We postulated the presence of Sr2, Sr6, Sr7a, Sr8a, Sr9b, Sr11, Sr12, Sr24, Sr25, Sr31, and Sr57 (Lr34) in this germplasm based on phenotypic and marker data. We found that combinations of genes conferring resistance to specific P. graminis f. sp. tritici races accounts for the prevalent stem rust resistance in North American spring wheat.
CSK Himachal Pradesh Agricultural University, Palampur, India
Aashima Bhateja, Ravi Sharma, Vijay Rana, Hanif Khan
Wheat crop is attacked by three rust diseases of which stripe rust, caused by Puccinia striiformis f. sp. tritici and leaf rust, caused by Puccinia triticina, are the most common causing greater yield losses. Thirty genotypes were studied for (APR) adult plant resistance and were evaluated in field conditions and controlled conditions. HPW 373, VW 20145, VL 3002, RKVY 231, VL 907, PBW 698 and HS 507 were found to be highly resistant to yellow rust at both seedling and adult plant stages. While, genotypes HS 490, HPW 314, HPW 360, RKVY 133, Raj 4362, DBW 113 and HPW 403 showing very low AUDPC values were found to be moderately resistant under field conditions. These lines are suggested for use in breeding program and some are in network trials for their direct release. Inheritance studies were carried out to decipher the genetics of seedling rust resistance in elite germplasm line HPW 373. The F2s were evaluated for seedling resistance against yellow rust (46S119, 78S84) and leaf rust (77-5-North American equivalent THTTM) races. Resistance in HPW 373 is controlled by single dominant gene against leaf rust (77-5) and stripe rust (78S84). Against stripe rust (46S119), resistance of HPW 373 is controlled by recessive gene. The findings are expected to contribute towards enriching diversity for leaf and stripe rust resistance in bread wheat improvement programmes.
Crop and Horticultural Science Research Department, Ardabil Agricultural and Natural Resources Research and Education Center, Ag
Yellow (stripe) rust caused by Puccinia striiformis f. sp. tritici is the most devastating disease of bread wheat (Triticum aestivum) in the world. A wide range of virulent yellow rust pathotypes is evolving in different regions of the world causing the breakdown of widely utilized sources of resistance in wheat. Hence, the knowledge of virulence factors of pathogen and determining of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programs. During cropping seasons of 2015-2016 and 2016-2017, virulence of the wheat yellow rust was investigated by planting differential cultivars and isogenic lines in a yellow rust trap nursery in Ardabil, northwest of Iran . Results showed stripe rust infections on some cultivars carrying Yr genes such as Yr1, Yr3, and Yrsp previously known to be resistant. The virulence spectrum of race population in Ardabil was identical to the Warrior race or its variants which is different from characterized races in Ardabil by carrying virulence combination for Yr1, Yr3, Yr17, Yr32, and YrSP and is avirulent on Yr8 and Yr27. Except for Yr8, Yr17 and Yr27, the common races in Ardabil are generally avirulent on Yr1, Yr3, and YrSP. This is the first report of race population in Ardabil (Iran) which is similar to the Warrior race or its variants.
Food and Agriculture Organization of the UN
Munira Otambekova, Bahromiddin Husenov, Alexei Morgounov
Wheat as a staple food crop in Tajikistan plays a crucial role for food security of population. However its production is threatened by number of limiting factors, and among them wheat rusts are most devastating disease.
Close collaboration of local scientists and breeders was established with International Agricultural Research Centers, including CIMMYT and ICARDA since early 2000. In the result, a number of high yielding and rust resistant varieties were released in Tajikistan that occupy presently about 40% of total wheat area.
Among the major breeding objectives selection of varieties with high resistance to wheat rusts, especially yellow rust considered as a priority task. The following new varieties originated from CIMMYT international nurseries were released in the country in past years, which bear high resistance to yellow rust: Sarvar (CHEN\AEGILOPS SQUARROSA (TAUS0//BCN/3/BAV92), Yusufi (SOROCA), Vahdat (VORONA SN079), Isfara (SW89.5181/KAUZ), Fayzbaksh (TAM200.KAUZ) and Shokiri (SHARK/F4105W2.1).
During the last three years eight new varieties were submitted for official testing, and two of them already are released in 2017 (Murodi and Durakhshon) and remaining ones are under official testing. The varieties and their origin are followings: Murodi (CHEN/AE.SQ//WEAVER/3/SSERI1), Durakhshon (ATTILA/3*BCN*2//BAV92), Kamol (PYN/BAU//LAGOS-19/3/ID800994.W/VEE), Zarnisor (CROC_1/AE.SQUARROSA(205)//BORL95/3/2*MILAN), Ganj (NAC/TH.AC//3*PVN/3/MIRLO/BUC/4/2*PASTOR), Mehrgon (SAAR/WAXWING), Sipar (FRET 2*2/4/SNI/TRAP #1/3/KAUZ*2/TRAP//KAUZ/5) and Lochin (PJN/BOW//OPATA*2/3/CROC_1/AE.SQ.(224)).
Ethiopian Institute of Agricultural Research, Debre Zeit Research Centre
Alemayehu,Chala, , , , , , , , , , , , , , , , , , , , , , , , , , , ,
Stem rust caused by Puccinia graminis f.sp. tritici is one of the major biotic constraints of wheat production. The disease may cause substantial quantitative and qualitative yield losses. However, much of the work in Ethiopia on this pathosystem focuses on quantitative yield loss and qualitative losses are often overlooked. Hence the current research was designed with the objectives to evaluate the effect of stem rust on physical and chemical quality of durum wheat and assess the relationships between disease intensity and quality parameters. For this purpose, a factorial field experiment was conducted at Debre Zeit Agricultural Research Centre during main and off seasons of 2016/17. The experiment involved six durum wheat varieties (Denbi, Hitosa, Tob.66, Mukiye, Ude and Mengudo) with different level of resistance to stem rust, and three Tilt spray schedules of Tilt?250 E.C at 7, 14 and 21 days. The experiment was laid out in randomized complete block design in factorial arrangements with three replications and untreated checks were included for comparison purpose. Results revealed significant variations in disease parameters and crop performance among spray schedules, wheat varieties and their interactions. Stem rust severity was the lowest on moderately susceptible and susceptible varieties treated with the Tilt at 7th day schedule. The highest stem rust severity (46.67%) was recorded on variety Hitosa without Tilt spray. Without Tilt treatment Denbi variety accounts protein content of 15.67% which is a false protein. At 7th day spray schedule this variety showed 12.90 % of grain protein content which is normal. There was a significant positive correlation between grain protein and stem rust severity (0.31**). There was significant negative relationships between terminal stem rust severity and thousand kernel weight, hectolitre weight, seed size and yield during off and main seasons were resulted, respectively.
Ayub Agricultural Research Institute, Faisalabad, Pakistan
Muhammad,Idrees, Faqir, Muhammad, Arshad, Mehmood, Majid, Nadeem, Saleem-ur, Rehman, Makhdoom, Hussain, Javed, Ahmad, , , , , , , , , , , , , , , ,
Under changing climatic conditions, the emergence of new diseases or new races of existing diseases is a serious threat to global wheat production. Particularly, the presence of wheat blast in Bangladesh and stem rust race Ug99 in Iran, created a fearsome and intractable situation for Pakistan. A study was planned for monitoring and surveillance of the wheat blast and rust pathogens in wheat growing districts of Punjab, Pakistan during the cropping season 2016-17 as vigilance program. During the survey, one hundred and seventy one wheat fields of upper and central Punjab region were monitored and two types of Rusts (Leaf Rust & Yellow Rust) were recorded in varying intensity on different varieties of wheat. Out of 171 locations 86 spots were free from both types of rusts i.e. Leaf Rust & Yellow Rust, while the remaining locations were found to be infected with both leaf and yellow rust. However, all the surveyed fields were free from the stem rust infestation. Among the infected fields, 23 were infected by Leaf Rust while 63 fields were infected by Yellow Rust.The susceptible type of rust attack was noticed on old/ banned/ unapproved wheat varieties. Moderately resistant to resistant reaction was observed on newly approved varieties. The rust infected samples having S or MS type infection were collected for race analysis. Similarly, blast suspected samples were analyzed in laboratory and none of the tested samples showed the presence of wheat blast pathogen, which indicates no need to panic but vigilant in future.
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.
University of Minnesota
Bedada,Girma, Bekele, Hundie, Endale, Hailu, Getaneh, Wonderufael, Bekele, Abeyo, Ayele, Badebo, Pablo, Olivera, Yue, Jin, Gordon, Cisar, Matthew, Rouse, , , , , , , , , ,
Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a significant disease limiting wheat yield in Ethiopia. Wheat varieties such as 'Digalu' with single major-effect stem rust resistance genes have not exhibited durable resistance in Ethiopia. Identifying wheat lines with adult plant resistance (APR) has been proposed as a strategy to select for durable resistance. Our objective was to test the hypothesis that APR to stem rust is non-race-specific. We selected 31 wheat lines (including 10 durum and 21 bread wheat lines) that were susceptible as seedlings to Pgt races TTKSK, TKTTF, and TRTTF. These 31 wheat lines and Digalu were evaluated in 2014 and 2015 at the Kulumsa Agricultural Research Center, Ethiopia. The lines were planted in 1 m rows and replicated twice in separate single-race-inoculated nurseries. The three single-race nurseries inoculated with Pgt races TTKSK, TKTTF, and TRTTF were separated by at least 100 m and included selective spreaders. Plot yield, thousand kernel weight (TKW), and visual disease responses were measured for each plot. We used a least-squared means test to detect differences in coefficient of infection and TKW of each line across paired race comparisons. Lines 'Park', 'CI11469', and 'CI12818' displayed significantly different coefficient of infections between races TTKSK and TRTTF. For CI11469 and CI12818, this difference was validated by significant differences in TKW. Significant differences in TKW were also detected between various race comparisons for 'ETHBW019', 'CI14798', 'CI15159', 'CI14618', and 'CI14094'. Our data demonstrated that APR in the selected germplasm was largely non-race-specific, but there were exceptions where race-specificity of APR was detected. These results have implications for resistance breeding and monitoring: testing of breeding material against prevalent Pgt races in target environments, not relying only on hotspot screening locations, and careful monitoring of deployed APR varieties are all warranted.
Department of Plant Pathology, North Dakota State University, Fargo, ND
James,Kolmer, Maricelis, Acevedo, , , , , , , , , , , , , , , , , , , , , , , , , ,
Leaf rust, caused by Puccinia triticina Erikss. (Pt), is the most widespread wheat rust disease. Information on the virulence and genetic diversity of Pt is important for understanding the pathogen evolution, and thus effective management of wheat leaf rust. We used 20 Thatcher wheat near isogenic lines to study virulence diversity of 102 Pt isolates collected from tetraploid wheat, common wheat, and Triticale worldwide. Seven races were found among 57 isolates collected from tetraploid wheat while 21 races were observed among 40 common wheat type isolates. Four races were identified among the five isolates collected from Triticale. A subset of 30 Pt were genotyped using the Restriction-Associated DNA (RAD)-Genotype By Sequencing (GBS) adapted for the Ion Torrent sequencing platform. Phylogenetic analysis on 30 isolates using 2,125 SNP markers showed eight clusters supported by high bootstrap values. We observed higher genotypic diversity in common wheat type isolates compared to that in tetraploid wheat type isolates. Generally, there was a correlation between virulence phenotypes and SNP genotypes. Phylogeny results suggest that RAD-GBS is promising as a new technique for the study of population genetics in P. triticina.