Showing papers on "Rust published in 2016"

Role of Alternate Hosts in Epidemiology and Pathogen Variation of Cereal Rusts.

Abstract: Cereal rusts, caused by obligate and biotrophic fungi in the genus Puccinia, are important diseases that threaten world food security. With the recent discovery of alternate hosts for the stripe rust fungus (Puccinia striiformis), all cereal rust fungi are now known to be heteroecious, requiring two distinct plant species serving as primary or alternate hosts to complete their sexual life cycle. The roles of the alternate hosts in disease epidemiology and pathogen variation vary greatly from species to species and from region to region because of different climatic and cropping conditions. We focus this review on rust fungi of small grains, mainly stripe rust, stem rust, leaf rust, and crown rust of wheat, barley, oat, rye, and triticale, with emphases on the contributions of alternate hosts to the development and management of rust diseases.

A review of wheat leaf rust research and the development of resistant cultivars in Canada

Abstract: Wheat leaf rust, caused by Puccinia triticina Eriks., is of worldwide concern for wheat producers. The disease has been an annual problem for Canadian wheat producers since the early days of wheat cultivation in the 1800s, and research focused on combating this disease began in the early 1900s. Significant progress was made towards understanding the epidemiology of wheat leaf rust and developing genetic resistance in many countries worldwide. This review paper focuses exclusively on the research and development done in whole, or in part, in Canada. An integrated approach to controlling wheat leaf rust consisted of research in the following areas: the early research on wheat leaf rust in Canada, breeding and commercialization of high quality rust resistant wheat cultivars, discovery and genetic analysis of leaf rust resistance genes, the population biology and genetics of the P. triticina/wheat interaction. This review summarizes the research in each of these areas and the connections between the d...

Host jumps shaped the diversity of extant rust fungi (Pucciniales)

Abstract: The aim of this study was to determine the evolutionary time line for rust fungi and date key speciation events using a molecular clock. Evidence is provided that supports a contemporary view for a recent origin of rust fungi, with a common ancestor on a flowering plant. Divergence times for > 20 genera of rust fungi were studied with Bayesian evolutionary analyses. A relaxed molecular clock was applied to ribosomal and mitochondrial genes, calibrated against estimated divergence times for the hosts of rust fungi, such as Acacia (Fabaceae), angiosperms and the cupressophytes. Results showed that rust fungi shared a most recent common ancestor with a mean age between 113 and 115 million yr. This dates rust fungi to the Cretaceous period, which is much younger than previous estimations. Host jumps, whether taxonomically large or between host genera in the same family, most probably shaped the diversity of rust genera. Likewise, species diversified by host shifts (through coevolution) or via subsequent host jumps. This is in contrast to strict coevolution with their hosts. Puccinia psidii was recovered in Sphaerophragmiaceae, a family distinct from Raveneliaceae, which were regarded as confamilial in previous studies.

Genome-Wide Association Mapping of Leaf Rust Response in a Durum Wheat Worldwide Germplasm Collection.

Abstract: Leaf rust (caused by Erikss. []) is increasingly impacting durum wheat ( L. var. ) production with the recent appearance of races with virulence to widely grown cultivars in many durum producing areas worldwide. A highly virulent race on durum wheat was recently detected in Kansas. This race may spread to the northern Great Plains, where most of the US durum wheat is produced. The objective of this study was to identify sources of resistance to several races from the United States and Mexico at seedling stage in the greenhouse and at adult stage in field experiments. Genome-wide association study (GWAS) was used to identify single-nucleotide polymorphism (SNP) markers associated with leaf rust response in a worldwide durum wheat collection of 496 accessions. Thirteen accessions were resistant across all experiments. Association mapping revealed 88 significant SNPs associated with leaf rust response. Of these, 33 SNPs were located on chromosomes 2A and 2B, and 55 SNPs were distributed across all other chromosomes except for 1B and 7B. Twenty markers were associated with leaf rust response at seedling stage, while 68 markers were associated with leaf rust response at adult plant stage. The current study identified a total of 14 previously uncharacterized loci associated with leaf rust response in durum wheat. The discovery of these loci through association mapping (AM) is a significant step in identifying useful sources of resistance that can be used to broaden the relatively narrow leaf rust resistance spectrum in durum wheat germplasm.

SEM/Micro-Raman Characterization of the Morphologies of Marine Atmospheric Corrosion Products Formed on Mild Steel

Abstract: The exposure of carbon steel to marine atmospheres gives rise to the formation of various corrosion products (lepidocrocite, goethite, magnetite, akaganeite, etc.) that present a wide variety of morphologies depending on the specific conditions of their formation. The literature on this topic is scarce and lacks a rigorous analytical characterization of the different morphologies seen in microscopic observation of rust surfaces under a scanning electron microscope. The research presented in this paper uses XRD and the powerful integrated SEM/Micro-Raman technique to characterize a series of morphologies commonly found in the rust that forms when mild steel is exposed to marine atmospheres. Two atmospheres with highly different chloride deposition rates (atmospheric salinity) have been considered. In the lower salinity atmosphere an adherent rust layer was formed on the steel, the outer surface of which layer exhibited a variety of SEM morphologies corresponding to lepidocrocite (mainly) and goethite. In the higher salinity atmosphere the thick rust layer formed on the steel was easily exfoliated (detached) and the morphologies on the inner surface observed using SEM were very different, corresponding mainly to akaganeite and magnetite.

Genetic diversity of spring wheat from Kazakhstan and Russia for resistance to stem rust Ug99

Abstract: The spring wheat belt of Western Siberia and Northern Kazakhstan covers more than 15 million ha. While moisture stress is the main factor limiting production, rusts also represent a major challenge, especially in years with higher rainfall. Stem rust was not considered economically important until 2015 when a local epidemic occurred in the Omsk region of Russia and neighboring areas of Kazakhstan and affected more than 1 million ha. It occurred again in 2016 though the spread, severity and losses were less. This study used 16 pathotypes and 17 molecular markers to characterize a set of 146 spring wheat varieties and breeding lines identified as stem rust resistant in Kenya and the Kazakhstan–Siberia region for the presence of major genes. The genetic basis of resistance in the material was limited to Sr25, Sr31, Sr36, Sr6Ai, Sr6Ai#2, and some unknown major genes. Genes Sr25 and Sr6Ai#2 also provided high levels of resistance to leaf rust through linkages with Lr19 and Lr6Ai#2. Adult plant resistance to stem rust was observed in 26 genotypes (16.5 %), including eight possessing Sr57 gene. The high risk of stem rust—as indicated by the 2015 Siberian epidemic—means that there is an urgent need to diversify the genetic bases of resistance and to promote resistant varieties with farmers.

The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

Abstract: Summary The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat.

Atmospheric Corrosion of Q235 Carbon Steel and Q450 Weathering Steel in Turpan, China

Abstract: Q235 carbon steel and Q450 weathering steel were exposed to the hot and dry environment of Turpan, China for three years The corrosion rates of both steels were calculated and compared The morphologies of the rust layer products were observed by optical microscopy and scanning electron microscopy Analyses of the rust layers were performed by X-ray photoelectron spectroscopy, X-ray powder diffraction, and Raman spectroscopy, and analysis results indicate that the compositions of rust are main iron rich oxide such as FeOOH, Fe3O4, and Fe2O3 The iron oxide layer content proportion was calculated through a semi-quantitative algorithm The resistance elements (Cr, Ni, and Cu) enhanced the resistance properties of the Q450 weathering steel matrix Moreover, the resistance elements increased the proportion of goethite crystals in the corroded rust layer

Meeting the challenge of yellow rust in cereal crops: proceedings of the regional conference on Yellow Rust in the central and West Asia and North Africa region, 8-14 May 2001, Karaj, Iran

Abstract: Meeting the challenge of yellow rust in cereal crops: proceedings of the regional conference on Yellow Rust in the central and West Asia and North Africa region, 8-14 May 2001, Karaj, Iran , Meeting the challenge of yellow rust in cereal crops: proceedings of the regional conference on Yell... , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Molecular mapping of a rust resistance gene R 14 in cultivated sunflower line PH 3

Abstract: Sunflower, the fifth largest oilseed crop in the world, plays an important role in human diets. Recently, sunflower production in North America has suffered serious yield losses from newly evolved races of sunflower rust (Puccinia helianthi Schwein.). The rust resistance gene, designated R 14 , in a germplasm line PH 3 originated from a wild Helianthus annuus L. population resistant to 11 rust races. PH 3 has seedling with an extraordinary purple hypocotyl color. The objectives of this study were to map both the R 14 rust resistance gene and the purple hypocotyl gene-designated PHC in PH 3, and to identify molecular markers for marker-assisted breeding for sunflower rust resistance. A set of 517 mapped SSR/InDel and four SNP markers was used to detect polymorphisms between the parents. Fourteen markers covering a genetic distance of 17.0 cM on linkage group (LG) 11 were linked to R 14 . R 14 was mapped to the middle of the LG, with a dominant SNP marker NSA_000064 as the closest marker at a distance of 0.7 cM, and another codominant marker ORS542 linked at 3.5 cM proximally. One dominant marker ZVG53 was linked on the distal side at 6.9 cM. The PHC gene was also linked to R 14 with a distance of 6.2 cM. Chi-squared analysis of the segregation ratios of R 14 , PHC, and ten linked markers indicated a deviation from an expected 1:2:1 or 3:1 ratio. The closely linked molecular or morphological markers could facilitate sunflower rust-resistant breeding and accelerate the development of rust-resistant hybrids.

Scanning electron microscopy/micro-Raman: A very useful technique for characterizing the morphologies of rust phases formed on carbon steel in atmospheric exposures

Abstract: The morphological structures displayed by iron oxides present a very wide range of shapes and sizes, reflecting to a large extent the growth environment where the iron has been exposed. However, th...

Development of a Greenhouse Screening Method for Adult Plant Response in Wheat to Stem Rust

Abstract: Screening for adult plant resistance in wheat to stem rust, caused by Puccinia graminis f. sp. tritici, is generally conducted in field plots. Although such evaluations are successful if managed properly, field ratings are time consuming, expensive, weather dependent, and open to inoculum of unwanted races or other confounding diseases. The objective of this study was to develop a dependable system of screening the response of adult plants to stem rust under greenhouse conditions. A comparison of inoculation methods and incubation environments showed that plants inoculated with urediniospores suspended in water, followed by a 24 h dew period in a plastic chamber constructed in a greenhouse, gave the most consistent results. Measurements of response type, stem rust severity, and frequency in follow-up experiments indicated that the most reliable infection was obtained when plants sprayed with 1.25 mg urediniospores per ml water were incubated in the plastic chamber. Using the optimized protocol, a Kariega × Avocet S doubled haploid population was inoculated with two P. graminis f. sp. tritici races. Depending on the race, composite interval mapping showed flag leaf infection type to be significantly influenced by regions on chromosomes 6A, 6D, and 7D. Stem rust severity and reaction type mapped to chromosomes 6D and/or 6A. The Lr34/Yr18/Sr57 gene derived from Kariega on chromosome 7D affected the rust response on flag leaves but not on stems of greenhouse-grown plants. This study showed that phenotyping and genetic analysis of especially major effect stem rust resistance in adult wheat plants is possible and reproducible under controlled conditions in a greenhouse.

Evolution of Initial Atmospheric Corrosion of Carbon Steel in an Industrial Atmosphere

Abstract: The evolution of initial corrosion of carbon steel exposed to an industrial atmosphere in Shenyang, China, has been investigated by gravimetric, XRD, SEM/EDS and electrochemical techniques. The kinetics of the corrosion process including the acceleration and deceleration processes followed the empirical equation D = At n . The rust formed on the steel surface was bi-layered, comprised of an inner and outer layer. The outer layer was formed within the first 245 days and had lower iron content compared to the inner layer. However, the outer layer disappeared after 307 days of exposure, which is considered to be associated with the depletion of Fe3O4. The evolution of the rust layer formed on the carbon steel has also been discussed.

Identification and Severity Determination of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data Acquired Using a Black-Paper-Based Measuring Method.

Abstract: It is important to implement detection and assessment of plant diseases based on remotely sensed data for disease monitoring and control. Hyperspectral data of healthy leaves, leaves in incubation period and leaves in diseased period of wheat stripe rust and wheat leaf rust were collected under in-field conditions using a black-paper-based measuring method developed in this study. After data preprocessing, the models to identify the diseases were built using distinguished partial least squares (DPLS) and support vector machine (SVM), and the disease severity inversion models of stripe rust and the disease severity inversion models of leaf rust were built using quantitative partial least squares (QPLS) and support vector regression (SVR). All the models were validated by using leave-one-out cross validation and external validation. The diseases could be discriminated using both distinguished partial least squares and support vector machine with the accuracies of more than 99%. For each wheat rust, disease severity levels were accurately retrieved using both the optimal QPLS models and the optimal SVR models with the coefficients of determination (R2) of more than 0.90 and the root mean square errors (RMSE) of less than 0.15. The results demonstrated that identification and severity evaluation of stripe rust and leaf rust at the leaf level could be implemented based on the hyperspectral data acquired using the developed method. A scientific basis was provided for implementing disease monitoring by using aerial and space remote sensing technologies.

Effect of integrated climate change resilient cultural practices on faba bean rust (Uromyces viciae-fabae) epidemics in Hararghe highlands, Ethiopia.

Abstract: Climate variability due to increasing temperature and erratic precipitation could affect faba bean rust disease epidemics and the crop productivity. Rust caused by Uromyces viciae-fabae is one of the serious foliar diseases of faba bean in Ethiopia. Field studies were conducted at Haramaya and Arbarakate during 2012 and 2013 to assess effects of integrated climate change resilient cultural practices on rust epidemics in the Hararghe highlands of Ethiopia. Three climate change resilient cultural practices: intercropping, compost application and furrow planting alone and in integration were evaluated using Degaga and Bulga-70 faba bean varieties and Melkassa-IV maize variety. Treatments were factorial arranged in a randomized complete block design with three replications. Faba bean-maize row intercropping and intercropping integrated treatments significantly reduced disease severity, AUDPC and disease progress rate. These treatments reduced rust mean severity by up to 36.5% (2012) and 27.4% (2013) at Haramaya, and up to 27% in 2013 at Arbarakate on both varieties as compared to sole planting. Compost fertilization also led to slow epidemic progression of rust and significantly reduced disease parameters when integrated with maize row intercropping. Compost fertilization in row intercropping recorded the lowest (23.1%) final mean disease severity and the highest (36.5%) percentage reduction in mean disease severity compared to sole cropping at Haramaya in 2012. The trend was similar in 2013 at both locations. Degaga had the lowest rust disease parameters studied compared to Bulga-70 at both locations over years. The overall results indicated that integrated climate change resilient cultural practices were effective to slow the epidemics of rust and to increase faba bean productivity. Hence, integrated climate change resilient cultural practices along with other crop management systems are recommended in the study areas.

McGISH identification and phenotypic description of leaf rust and yellow rust resistant partial amphiploids originating from a wheat × Thinopyrum synthetic hybrid cross

Abstract: A Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid wheatgrass is an excellent source of leaf and stem rust resistance produced by N.V.Tsitsin. Wheat line Mv9kr1 was crossed with this hybrid (Agropyron glael) in Hungary in order to transfer its advantageous agronomic traits into wheat. As the wheat parent was susceptible to leaf rust, the transfer of resistance was easily recognizable in the progenies. Three different partial amphiploid lines with leaf rust resistance were selected from the wheat/Thinopyrum hybrid derivatives by multicolour genomic in situ hybridization. Chromosome counting on the partial amphiploids revealed 58 chromosomes (18 wheatgrass) in line 194, 56 (14 wheatgrass) in line 195 and 54 (12 wheatgrass) in line 196. The wheat chromosomes present in these lines were identified and the wheatgrass chromosomes were characterized by fluorescence in situ hybridization using the repetitive DNA probes Afa-family, pSc119.2 and pTa71. The 3D wheat chromosome was missing from the lines. Molecular marker analysis showed the presence of the Lr24 leaf rust resistance gene in lines 195 and 196. The morphological traits were evaluated in the field during two consecutive seasons in two different locations.

Postulation of rust resistance genes in Nordic spring wheat genotypes and identification of widely effective sources of resistance against the Australian rust flora

Abstract: Wild relatives, landraces and cultivars from different geographical regions have been demonstrated as the sources of genetic variation for resistance to rust diseases. This study involved assessment of diversity for resistance to three rust diseases among a set of Nordic spring wheat cultivars. These cultivars were tested at the seedling stage against several pathotypes of three rust pathogens in the greenhouse. All stage stem rust resistance genes Sr7b, Sr8a, Sr12, Sr15, Sr17, Sr23 and Sr30, and leaf rust resistance genes Lr1, Lr3a, Lr13, Lr14a, Lr16 and Lr20 were postulated either singly or in different combinations among these cultivars. A high proportion of cultivars were identified to carry linked rust resistance genes Sr15 and Lr20. Although 51 cultivars showed variation against Puccinia striiformis f. sp. tritici (Pst) pathotypes used in this study, results were not clearly contrasting to enable postulation of stripe rust resistance genes in these genotypes. Stripe rust resistance gene Yr27 was postulated in four cultivars and Yr1 was present in cultivar Zebra. Cultivar Tjalve produced low stripe rust response against all Pst pathotypes indicating the presence either of a widely effective resistance gene or combination of genes with compensating pathogenic specificities. Several cultivars carried moderate to high level of APR to leaf rust and stripe rust. Seedling stem rust susceptible cultivar Aston exhibited moderately resistant to moderately susceptible response, whereas other cultivars belonging to this class were rated moderately susceptible or higher. Molecular markers linked with APR genes Yr48, Lr34/Yr18/Sr57, Lr68 and Sr2 detected the presence of these genes in some genotypes.

SVM application in hazard assessment: Self-heating for sulfurized rust

Abstract: In order to assess the oxidation self-heating hazard of sulfurized rust, for particular ambient conditions in crude oil tanks, the support vector machine (SVM) technique is applied to predict the maximum temperature ( T max ) of oxidation self-heating process. Five governing parameters are selected, i.e. the water content, mass of sulfurized rust, operating temperature, air flow rate and oxygen concentration in the respiratory/safety valve. The efficiency and validity of the SVM predictions are investigated in the case of two sets of data: more than 85 experiments performed in academic lab (China) and almost 17 additional results collected from existing literature. Two main steps are also discussed: the training process (on selected subsets of data) and prediction process (for the remaining subsets of data). It can be concluded that for both datasets the maximum temperature ( T max ) values calculated by SVM technique were in good accordance with the experimental results, with relative errors smaller than 15% except for a few cases. The SVM technique seems therefore to be relevant and very helpful for complex implicit processes such as chemical reactions, as it is the case of the oxidation of sulfurized rust in oil tanks. Furthermore, such predictive methods can be continuously be improved through additional experiments feedback (larger databases) and can then be of crucial help for monitoring and early warning of hazardous reactions.

Preparation and properties of natural gallic acid based rust conversion emulsion

Abstract: Purpose The paper developed a novel gallic acid-based rust conversion emulsion (RCE) that is applied in the treatment of rusted steels. The purpose of this paper is to investigate the methods for the synthesis of RCE and study the mechanism of rust conversion. Design/methodology/approach Conversion emulsion was prepared using styrene, acrylate and self-developed gallic acid (GA)-based rust converter (GRC) via seed emulsion polymerisation. The polymerisable GRC was synthesised by the ring-opening reaction of glycidyl methacrylate with natural GA. The effects of the GRC dosage and its feeding modes on the RCE synthesis were analysed. The corrosion resistance, surface morphology, composition and mechanism of rust conversion coatings were studied using electrochemical tests, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. Findings The results showed that conversion coating on rusted steels treated with RCE, with various dosages of GRC (weight per cent), synthesised using seed emulsion polymerisation, exhibited the best adhesion and corrosion resistance. Raman spectroscopy revealed that RCE converted the original multiphase rust into stable crystalline phases of α-Fe2O3 and Fe3O4. According to XPS and energy dispersive X-ray analysis, the phenolic hydroxyl groups of RCE were proposed to chelate with Fe ions to form macromolecular ferrum compounds. Research limitations/implications The pre-rusted steels demonstrated a better corrosion resistance than rust-free steels after treatment with RCE. Practical implications The paper developed a novel GA-based RCE with high efficiency and environment-friendly method. Originality/value This work is expected to replace the conventional rust conversion paints and cause a significant impact on extending the service life of rusted steels.

Evolution of the Rust Layers Formed on Carbon and Weathering Steels in Environment Containing Chloride Ions

Abstract: To clarify the correlation between alloy elements and growth pattern of the rust layers, the rusting evolution of the carbon and weathering steels was investigated by using the gold markers method. The corrosion experiments were carried out in a simulated environment containing chloride ions. The results indicate that Ni, Cu, Cr and Mo elements in the weathering steel suppress the rust crystallization and impede the rust layer growth to an internal development, and the suppression function benefits the formation of a protective rust layer. Moreover, γ-FeOOH is mainly located in the outer rust layer, while β-FeOOH is mainly located in the inner rust layer, and the distribution of the rust compounds in the rust layer is closely related to the growth pattern of the rust layer.

Identification of Leaf Rust Resistance Genes in Wheat Cultivars Produced in Kazakhstan

Abstract: Leaf rust, caused by Puccinia recondita f. sp. tritici, is one of the major diseases of wheat in Kazakhstan. To effectively use leaf rust resistance genes (Lr), it is important for breeders to know the resistance genotype in current cultivars. In this study, 30 winter wheat entries grown and/or produced in Kazakhstan were investigated using molecular markers to determine the presence and absence of eight important Lr genes. Molecular screening of these genotypes showed contrasting differences in the frequencies of these genes. Among the 30 entries, 17 carried leaf rust resistance gene Lr1, six had Lr26 and Lr34, and Lr10 and Lr37 were found in three cultivars. Two single cultivars separately carried Lr19 and Lr68, while Lr9 was not detected in any genotypes in this study. Field evaluation demonstrated that two of the most frequent two genes (Lr1 and Lr26) to be ineffective. While Lr34 provided some protection, the remaining effective Lr genes were found only in few genotypes: Lr37 occurred in Kazakh genotypes L-1090 and Krasnovodapadskaya 210 and in the US cultivar Madsen; Lr19 and Lr68 were likely present only in Russian and Kazakh cultivars, Pallada and Yegemen, respectively. The highest resistance over three years of leaf rust testing was found in Kazakh cultivars, Karasay, Krasnovodapadskaya 210, L-1090, Arap and Yegmen, foreign cultivars Madsen, Pallada and the control Parula (Lr68). Data may assist breeders to incorporate effective Lr genes into new cultivars.

Ug99:Saga, Reality and Status

Abstract: Wheat, the second most important cereal crop after rice, plays an important role in food and nutritional security worldwide. Wheat rusts, viz. black or stem rust (Puccinia graminis f. sp. tritici ), brown or leaf rust (P. triticina ) and yellow or stripe rust (P. striiformis ), capable of spreading aerially over long distances, are highly variable and devastating pathogens.

Rust diseases of wheat

Abstract: Rust diseases of wheat , Rust diseases of wheat , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی