International Center for Agriculture Research in Dry Areas (ICARDA)
ahmad amri, El-Haddoury Jamal
Constant climatic change and rapid evolution of diseases and pests have created challenges for plant breeders to find novel sources of resistance within cultivated gene pool. However wild (alien) relatives of crops still carries many promising resistance genes to biotic and abiotic stresses. Plant breeders around the world have successfully attempted to recover some of the beneficial genetic diversity lost (or never included) during the domestication and crop improvement process by crossing cultivated varieties with wild species to introgressed many valuable genes into crops like wheat and barley. This pre-breeding attempt to regain the genetic diversity of crops based on crop wild relatives (CWR) had been started at ICARDA 1994. Furthermore, The Global Crop Diversity Trust (GCDT) recently provided a grant to ICARDA within the Crop Wild Relatives (CWR) project to strengthen the research on use of genetic resources in pre-breeding of barley and grass pea. The pre-breeding activity in barley is focused on transferring genes of resistance to complex diseases and pests (scald, spot blotch and barley gall midge), improving tolerance to drought, heat and salinity, and enhancing the nutritional value through improving Iron and Zinc concentrations and amylases activity. Crosses were made between wild barely H. Vulgare X cultivated barley H. Vulgare subsp. H. spontaneum. The main objective of pre-breeding in Grasspea is transferring genes of low or no ?-ODAP from crossable species L. cicera and L. amphicarpus, L. tingitanus, L. aphaca, L. odoratus, L. sphaericus, L. nissolia, and L. aureus. Interspecific crosses were made between L. sativus x L.cicera followed by embryo rescue. Currently all the pre-breeding lines with targeted traits are under screening against the respective selection pressures using precision phenotyping..
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, St. Paul, MN 55108, U.S.A
Ruth Dill-Macky, Ruth Wanyera, Sridhar Bhavani, Worku Bulbula, Matthew Rouse
Stem rust caused by Puccinia graminis f.sp. tritici (Pgt) is one of the major constraints to wheat (Triticum aestivum) production worldwide. Pgt races have rapidly evolved in several geographical regions due to the deployment of single resistance genes resulting in boom and bust cycles, hence combinations of resistance genes through pyramiding ensures durability of resistance in wheat varieties. Spring wheat line CI14275 displayed high levels of field resistance to stem rust in Kenya and USA compared to the parents in its pedigree (Thatcher, Kenya Farmer & Lee). To understand the genetics of resistance in CI14275, 114 Recombinant Inbred lines (RILs) were developed from the cross CI14275/LMPG-6 and screened for seedling response to Pgt races TTTTF, TPMKC, TRTTF, TTKSK & RTQQC. Chi-square goodness of fit tests suggested one-gene, three-genes, and four-genes segregated for response to races TTTTF, TPMKC and RTQQC, respectively. The RILs were all susceptible to races TTKSK and TRTTF. CI14275 showed intermediate low infection types only against races TPMKC (23-) and TTTTF (1+3C). Field screening of the population was completed in Kenya, Ethiopia and St. Paul where CI14275 showed high levels of resistance TMR (Kenya), 5MS (Ethiopia) and 5RMR (St. Paul) against the prevalent races in the stem rust screening platforms. LMPG-6 displayed susceptible responses ranging from 70S-90S in the three locations. 90K wheat Single Nucleotide Polymorphism (SNP) marker platform will be used to genotype parents and the population.
Department of BioEngineering, Birla Institute of Technology, Mesra, Ranchi, India
Manish Kumar, Kunal Mukhopadhyay
Bread wheat (Triticum aestivum L.) being the world's most popular edible cereal, plays a major role in global economy. Rust in wheat leaves, caused by Puccinia triticina, affects grain quality and severely retards its production worldwide. Micro(mi)RNAs are considered major components of gene silencing and so have a great role to play during stress. The present study focuses on identification of miRNAs, produced by host to suppress pathogen as well as delivered by pathogens to encounter host defence mechanism. Therefore, these miRNAs may be called as leaf rust responsive microRNAs. Small RNA and degradome libraries were prepared from a pair of near isogenic lines of wheat (HD2329, HD2329+Lr24), one set was mock inoculated while the other set was inoculated with urediniospores of leaf rust pathogen. Using these libraries as input a vast number of miRNAs rather a population of miRNAs were identified derived from wheat that were targeting genes mostly involved in functions like defense response, signal transduction, development, metabolism, and transcriptional regulation.
When reads specifically produced under pathogen inoculation were taken as input with Puccinia triticina genome sequences as reference, only three putative miRNA precursor loci were detected and the molecules produced were called miRNA-like molecules as their precursors lacked one or two criteria essential for a true miRNA precursor. The identified miRNAs were targeting genes like F-box protein, MAP kinase, calmodulin and susceptible antioxidant protein. We further identified the presence of argonaute and dicer like domains in Puccinia proteome available at FungiEnsembl which strengthens presence of RNAi-like activities in Puccinia.
In addition, differential expression of wheat as well as Puccinia small RNAs using stem loop RT-PCR under varying time points of disease progression (0-168 hpi) revealed their direct connection with stress responses.
Wheat Research Institute, Ayub Agricultural Rsearch Institute Faisalabad
Amna Kanwal, Mehwish Makhdoom, Javed Ahmed, Makhdoom Hussain
Wheat is the most important cereal crop in Pakistan because it contributes major portions of daily calorie intake. Rust is an increasing threat to wheat production and ultimately food security in Asian countries. The purpose of the present study is to identify the suitable wheat lines that could significantly resist rust pathogen without compromising yield. 60 durum wheat lines, entered in preliminary and regular yield trials, were tested for various morphological and physiological traits along with adult plant disease reaction under natural rust infestation. Results indicated that there was higher incidence of yellow rust as compared to leaf rust as ten genotypes were susceptible to leaf rust. Whereas seven lines were moderately susceptible, 14 were moderately resistant and two were completely susceptible to yellow rust. These findings suggested that future breeding program should be directed towards the developments of resistant cultivars that could resist variable strains of rust pathogen under changing climatic conditions.
The University of Jordan
Ayed Al Abdallat, Monther Tahat
Studies on whet stem rust (WSR) in Jordan are considered to be old. There was only one study conducted in the late 1980's by Abu-Blan and Duwayri (1989) to evaluate the infection of wheat cultivars with black stem rust disease (Puccinia graminis f. sp. tritici). Recently, reports of stem rust were published in Israel and Lebanon in 2010 and first report of Ug99 was reported in Egypt in 2014. The objectives of our research are to: (i) survey wheat growing areas for WSR in Jordan during the years 2017-2020, (ii) identification of WSR races isolated from Jordan morphologically and molecularly, (iii) analyze rust populations in terms of their response to known differential sets, pathotype distribution and diversity, (iv) screening the response of Jordanian wheat germplasm to the identified WSR strains, and (vi) study the population diversity of WSR races using RT-PCR and SNP genotyping. In 2017 a total of 270 fields of wheat and barley in the wheat and barley growing areas in Jordan were surveyed from March-May. The survey covered northern, middle, and southern parts of Jordan (arid and semi-arid regions). Altitude, longitude, and latitude data was recorded. Only few WSR pustules (n=4) were collected because the environmental conditions were not suitable for the disease to develop. On the other hand, wheat stripe rust was very common in the wheat growing areas mainly at the southern parts of the country. Other fungal plant pathogens were also reported including smuts, spots, blotches, powdery mildew, crown rot, fusarium head blight, and flag smut.
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.
Global Rust Reference Center (GRRC), Aarhus University, Denmark
Mogens Støvring Hovmøller, Jens Grønbech Hansen, Annemarie Fejer Justesen, Tine Thach, Julian Rodriguez-Algab, Dave Hodson, Biagio Randazzo
In 2016, severe epidemics of yellow (stripe) rust were observed on durum and bread wheat in European regions where the diseases in the past were insignificant or absent. Stem rust was also observed at epidemic levels for the first time in more than 50 years in Europe. On Sicily, both yellow and stem rust caused epidemics on cultivated durum and bread wheat and numerous breeding lines. In 2017, surveys in farmer fields and trial monitoring were carried out in Southern Italy during April-June. A total of 61 farmer fields and 9 experimental plots were inspected and rust samples collected. Despite unfavourable weather conditions for rust development, stem rust, yellow rust and leaf rust were detected on 86%, 50% and 14% of the surveyed sites, respectively. The surveys on Sicily covered approximately 70% of the durum wheat area, and data uploaded and visualised on the Wheat Rust Toolbox. On mainland Italy and Sardinia, yellow rust was observed, and sampled from nine fields in Sardinia and two in Puglia, whereas stem rust was detected and sampled in experimental plots in Sicily, Sardinia, Puglia, Lazio and Emilia Romagna. A total of 94 samples of stem rust, 30 samples of yellow rust, and 3 rust samples from Berberis aetnensis were sent to GRRC. Preliminary results of yellow rust genotyping and race phenotyping showed prevalence of race Triticale2015. Warrior(-) and a new race (Pst'New'- First detected in 2016) were also detected. For stem rust, TTTTF and TTRTF were detected in Sicily and mainland Italy and TKTTF was identified in Sardinia. Susceptibility of major commercial durum cultivars and breeding lines suggests the need for both durable resistance breeding and systematic surveys coupled to an early warning system.
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.
Lake Chad Research Institute, Maiduguri, Borno State-Nigeria
Dattijo Aminu, Zakari Goji Silas Turaki, Fatima Henkrar, Udupa Sripada
The research was conducted at ICARDA, Rabat. Twenty-four accessions were obtained from LCRI for marker analysis. Wizard Genomic DNA Purification Kit was used for DNA extraction. DNA was extracted by CTAB method and quantified using 1.0 % (w/v) agarose gels. Total of 12 loci, 5 functional and 7 linked random DNA markers to the traits of interest were used. PowerMarker and DARwin software were used to calculate the No. of alleles and values of genetic diversity, PIC, genetic distance, and NJ dendrogram. The total No. of detected alleles was 39; and mean No. of alleles was 3.25. No. of alleles range from 1 (Dreb-B1) to 9 (Xgwm577). Genetic diversity index ranged from 0.0000 in Dreb-B1 to 0.8471 in Xgwm577. The PIC value was also varied from 0.0000 (Dreb-B1) to 0.8296 (Xgwm577). The frequency of biotic resistance linked random DNA marker allele at Xgwm144 and Xwmc44, associated with yellow and leaf rust gene was 25% each. Marker alleles Xgwm577 and Xgwm533 linked to Stb2 and Stb8 at 150 and 120bp have frequencies of 21 and 4%. The frequency of abiotic resistance showed 50% of accessions had 1R segment (1BL.1RS translocation) and 58% of accessions showed presence of 120bp allele of Xwmc89, associated with QTL for drought tolerant. Functional marker alleles of Dreb-B1 associated with drought tolerant genes showed alleles frequency in all accessions. Linked marker allele Xgwm111 linked to heat tolerant gene showed 17% allele frequency at 220bp. Rht1 and Rht2, the allele frequencies were 92 and 4%. 92% of the cultivars had photoperiod insensitive allele at Ppd-D1 locus. VrnA1a and VrnA1c primer pair amplified at 965, 876, and 484bp, allele frequency of 13 and 87%. Cluster analysis had grouped the accessions into 5 at a genetic distance level 0.15.