Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Kamal Shahbazi, Jabbar Alt Jafarby, Mohammad Sadegh Khavarinejad, Farzad Afshari, Farshad Bakhtiar, Habibollah Soghi
In this project to obtain resistant wheat breeding lines/cultivars to stem rust disease, new cultivars and lines of the north breeding program were evaluated in greenhouse with races collected in 2014 from northern regions of Iran, Moghan and Gorgan. Artificial inoculation in greenhouse indicated none of the races had virulence on Sr11, Sr13, Sr24, Sr25, Sr26, Sr27, Sr29, Sr31, Sr32, Sr33, Sr37, Sr39, Sr40, and SrTmp. In order to evaluate seedling resistance, 143 wheat cultivars and new lines under greenhouse conditions were inoculated with four isolates of stem rust in four separate experiments in a randomized complete block design with three replications. Evaluation of the northern germplasm under greenhouse conditions showed that some of the genotypes were resistant against all four isolates. The resistance of some of these new lines was also confirmed in Kenya. Regarding other desirable agronomic characteristics, some of these lines will be introduced as new cultivars in the northern region of Iran.
P. triticina has a biotrophic relationship with wheat and needs certain elements from the wheat host for a successful life cycle. In recent years, several long lasting, minor resistance genes have been cloned, and their function suggests that the resistance is not due to a classic NB-LRR gene, but a gene that functions in a biotrophic pathway. The hypothesis was proposed that modification of a susceptibility gene can provide broad, long lasting resistance. To test this hypothesis, Thatcher was treated with EMS and screened for changes in susceptibility. M5 lines were evaluated in the greenhouse with BBBD Race 1 and 5 lines were identified. Also, M5 lines were planted in the field to verify the resistance and test the resistance effectiveness to natural infections of P. triticina. The same five lines were resistant in the field. Resistance ranged from few pustules, a race specific-like reaction, lesion mimics with few or no pustules, and near immunity. These lines were backcrossed to Thatcher, and resistant F2 plants were bulked and sequenced. Gene candidates will be identified and discussed.
Laboratoire de Biologie, Eau et Environnement, département d'écologie,university of 8 mai1945 Guelma, Algeria
Epidemics of stripe (yellow) rust on wheat and triticale fields of Algeria in 2016. Wheat and triticale fields in 69 localities from the eastern regions of Algeria were assessed for epidemics, which started in early march to late may corresponding to booting stage up to early dough stage of the alternative type crop. The infection had incidences ranging from 30 to 100% and severities of 30 to 70%. The newly released cultivar Ksar sbahi was infected up to 10%. The old improved durum cultivars HAR3116 (SHA7/KAUZ) and HAR1407 (COOK/VEES//DOVES) were rust-free at a number of locations. In the Amhara region, the wheat cultivars were at stem elongation to flowering with disease incidences of 50-100% and severities of 30-90%. The oldest cultivar ET 13 A2 was severely infected in the north Shewa zone of Amhara region. Triticale cultivar Logaw Shibo was susceptible at elevations above 2700 m and showed trace reactions at elevations below 2500 m. The local bread wheat cultivar grown in all wheat growing areas was only slightly affected by the disease. Yellow rust was rarely recorded in the Tigray region. Severe epidemics were recorded in the highlands and even at lower elevations where it is not commonly found on wheat.
Agharkar Research Institute Pune
Vijendra Baviskar, Balgounda Honrao, yashavanthakumar kakanur, Vilas Surve, Deepak Bankar, Vitthal Gite, Ajit Chavan, Vijay Khade, Juned Bagwan, Shrikant Khairanar, Sameer Raskar
Frontline demonstrations (FLDs,) on wheat were conducted by Agharkar Research Institute, Pune, during last five rabi seasons from 2012-13 to 2016-17 at farmer's fields of Pune and Satara district under wheat growing area of semi-arid tropics of western Maharashtra, India. Before conducting FLDs, a group meeting held every year in the selected village and specific skill training had imparted to the randomly selected farmers regarding adoption of different improved aspects of cultivation. FLDs comprised of improved wheat varieties viz., MACS 6222, MACS 6478, MACS 3125 (d) and MACS 2971(dic) for Peninsular Zone of India. About 50 ha of FLDs on improved wheat varieties were conducted with active participation of 50 farmers covered an average of 10 farmers and 10 ha per year. Two recent varieties, MACS 6222 and MACS 6478 had shown higher grain yield, ranging between 15 to 55 per cent more over local check and farmer practice than all other FLDs. Recommended packages and practices of wheat FLDs gave higher value of yield, net return and high benefit cost ratio as compared to local check over the years of study. The study has revealed that five years mean extension gap of 4.48 to 9.67 q/ha and technology gap ranging between 11.00 to 22.22 q/ha depending on the variety during the period of study. Net returns of Rs. 63042/ha was observed from improved practice than in the farmer's practice of Rs. 50108/ha and with benefit cost ratio of 3.07 and 2.79 respectively. On average basis, the incremental benefit cost ratio was found as 2.83. In frontline demonstrations, the yield potential of wheat has been enhanced largely due to the increase in the knowledge of farming community and adoption of improved production techniques by farmers.
Research Institute of Crop Husbandry, Azerbaijan
ATIF,ZAMANOV, Konul, Aslanova, , , , , , , , , , , , , , , , , , , , , , , , , ,
Rust diseases are considered the main stress factors that limit wheat productivity in the Azerbaijan. The studies on the impact of rust diseases on physiological processes at reproductive vegetation period is of very importance with view of evaluating size of yield and quality of the studied genotypes. For this purpose the studies focused on bread wheat genotypes (Triticum aestivum L.), which differ sharply by architectonics, biological peculiarities and resistance to rust diseases. Comparative evaluation of the studied genotypes by physiological and quality parameters has been undertaken in two options: over plants infected with diseases in natural background, and over healthy plants (fungicide sprayed plants). Area of photosynthesis apparatus of leaf story (18,3-50,2 sm2) of the studied wheat genotypes changes in wide interval. Infestation level of leaves with yellow rust (Puccinia striiformis West.) in wheat genotypes grown in natural infection background fluctuates between 5MS-40S in ontogenesis, but between 10MS-90S with brown rust (Puccinia recondita Desm.).
High level of infection with rust diseases leads to reduced size of leaf assimilation area and defoliation. Reduction of these dimensions makes up 10-90% in lower story leaves of genotypes infected with rust diseases, but 20-30% in upper story leaves. Genotypes with large and bending leaves subject to this disease more frequently. Value of photosynthesis intensity in ontogenesis at upper story leaves of the genotypes infected with rust diseases at natural background fluctuates between 6-18 ?mol CO2 .m-2.s-1 depending on level of infection, but in healthy plants between 16-29 ?molCO2 .m-2.s-1. Negative impact of these diseases on normal course of plant physiological process ultimately causes is reflected in yield and quality parameters.
University of Minnesota
Ayele Badebo, Worku Bulbula, Matthew Rouse, Yue Jin
Our research objective is to identify new resistance genes in durum wheat that are effective against TTKSK and other significant stem rust pathogen races that could be utilized in durum breeding. We characterized 8,000 accessions for stem rust response in the field (Debre Zeit, Ethiopia, and St. Paul, MN). Accessions with resistant to moderately resistant responses in multiple field evaluations were evaluated at the seedling stage for resistance to races TTKSK, TRTTF, TTTTF, JRCQC, TKTTF, and six representative U.S. races. We identified 438 durum accessions resistant to moderately resistant in all field evaluations. Among the field-resistant accessions, 273 were resistant to all races used in seedling evaluations. Accessions susceptible at the seedling stage are being evaluated for the presence of adult plant resistance genes. The highest frequencies of resistant lines include landraces from East and North Africa (Ethiopia and Egypt) and advanced breeding lines and cultivars from North America (Mexico and USA). DNA markers will be performed to identify the presence of durum stem rust resistance genes, including Sr13, Sr8155B1, Sr11, and Sr8a. Nineteen resistant accessions were selected to investigate the genetics of TTKSK and TRTTF resistance. Results from evaluating F2 and F2:3 generations from biparental crosses revealed that resistance to race TTKSK was conferred mostly by one or two genes with dominant and recessive actions. Additional resistance genes were identified when populations were evaluated against race TRTTF. A bulk segregant analysis approach is being used to map the resistance in selected lines using the 90K SNP platform.
University of Delhi South Campus, New Delhi
Towards understanding the molecular mechanisms of heat stress tolerance, we have analyzed heat stressed substractive cDNA libraries and undertaken genome-wide transcriptome exploration for genes associated with spike photosynthetic efficiency during thermal stress. The photosynthetic efficiencies of Aegilops tauschii and Ae. speltoides were also compared. While the former displayed nearly complete recovery of PSII, the adverse effect was more pronounced in the latter. Functional characterization of heat stress-associated transcription factors and thermal stress-associated proteins was also undertaken e.g. TaHSF, TabZIP, TaZnF and TaMIPS, and TaLTPs in the Indian wheat germplasm. Functional characterization of the three heat stress transcription factors was upregulated under high temperatures and other abiotic stresses. They also showed early flowering and better performance with respect to their growth and yield after heat stress. Additionally, we have identified various interacting components associated with thermal stress-mediated plant signaling partners during thermal stress.
Agriculture & Agri-Food Canada
Wheat cultivar McNair 701 carries resistance gene SrMcN and is used as a differential line to identify Pgt races using the international letter code nomenclature. The inheritance and location of the resistance gene has not been characterized. We developed a doubled haploid (DH) population from cross LMPG/McNair 701 to study the genetics and chromosomal location of SrMcN. A DH population inoculated with race QCCJB segregated 100 resistant : 94 susceptible, a 1:1 ratio (?2=0.186, P=0.666, NS) indicative of segregation at a single locus. This gene was mapped to chromosome 2DL using the Infinium 90k platform. The map position of SrMcN was similar to that of Sr54, one of two genes previously found in Norin 40. Comparison of stem rust seedling reactions using 12 diverse Pgt races indicated that McNair 701 and an Sr54 line derived from Norin 40 had an identical pattern of responses and similar low infection types (IT=12-) to races LCBNB and QCCJB. Based on the chromosomal location on 2DL and identical seedling responses to Sr54, it is likely that the resistance gene in McNair 701 formerly known as SrMcN is Sr54. This finding will be confirmed by a test of allelism.
Wheat Research Institute, Faisalabad, Pakistan
Ghulam Mahboob Subhani, Javed Ahmad, Abid Mahmood
Global warming affects the environmental parameters of agro-based countries like temperature increase, melting of glaciers, floods, erratic rains, low temperature, frost and high temperature. As a result agriculture is becoming more vulnerable to global environmental shifts. In case of wheat, erratic or low rains badly affect the wheat crop of rainfed areas of the country along with high temperature at seedling or juvenile stage. Similarly, frost affects the early sown wheat crop in irrigated areas of Punjab. Lesser availability of irrigation water from water reservoirs also reduces the wheat crop productivity. Sudden increase in temperature (>30?C) during the month of March adversely affect the grain filling. High temperature during grain filling stage interferes with the photosynthetic activities of the plant due to enhanced maturity, grain become shriveled and results in low grain yield. The threat of these environmental changes can only be overcome through breeding with specific objectives which is cost effective once obtained.
Hence development of wheat varieties for frost, drought and heat tolerance is the only feasible solution to combat these stresses which is being used at Wheat Program of Ayub Agricultural Research Institute, Faisalabad, Pakistan. New emphasis is also being given to develop frost resistant wheat varieties due to changing scenario of last few years. The institute is actively involved for the development of heat, drought and frost tolerant wheat varieties. During working for tolerance against any of these stresses plant types to be breed are physiologically and morphologically modeled in such a way that they should be capable of tolerating respective stress. In addition to breeding work an extensive research is also being done at Wheat Research Institute, AARI., Faisalabad to investigate best agronomic strategies to make wheat crop best adapted to environmental stress conditions.
Laboratory of Molecular Plant Physiology, Biotechnology Center of Borj Cedria (CBBC)
Mahmoud Gargouri, Hesham A.Y Gibriel, Richard B. Todd, Michael F. Seidl, Gerrit H.J. Kema
Septoria tritici blotch disease, caused by the fungus Zymoseptoria tritici, is a major threat to global wheat production. With the recent advances in high-throughput DNA-based technologies, Z. tritici has become a powerful model system for the discovery of candidate determinants that underlie virulence and host specialization. Although a few important virulence/regulatory genes have been identified, a global understanding of the larger regulatory network has not been developed. Therefore, to uncover the transcriptional regulatory networks of the infection cycle and most particularly the regulatory hubs that control the switch between the biotrophic and necrotrophic phases, we applied an integrated approach combining transcriptomics, proteomics, and metabolomics analyses based on the identification of plant and fungal transcription factors and regulators, which we characterized from the newly annotated genome sequence of the reference isolate IPO323 (Grandaubert et al., 2015) and using datasets from Rudd et al. (2015). Bread wheat transcription factors and regulators were identified by querying the proteome and subsequent categorization from the Plant Transcription Factor database (PTFDB). Similarly, Z. tritici transcription factors and regulators were identified and categorized using the PFAM TF family databases, and following fungal transcription factor rules as outlined by Todd et al. (2014) and rules we developed for fungal transcription regulators. Insights into transcription factors and regulators will enable synthetic biology approaches to alter the Z. tritici-wheat interaction and lead to rewiring of the regulatory networks thereby turning off the fungal infection process. Beyond providing insights into the regulatory systems-levels involved in Z. tritici-wheat interaction, we believe that our dataset and approach sets the stage for an emerging series of studies that will decipher the dynamic regulatory networks in other plant-pathogen interactions.