Silvia A. Pereyra

National Institute of Agricultural Research of Uruguay (INIA Uruguay) · Crops Pathology

Fusarium head blight (FHB) is a destructive disease of cereal grains caused by several Fusarium species, of which Fusarium graminearum is considered the primary causal agent. In this work 586 pure cultures of Fusarium spp. were obtained from infected grains, of which 64.9% belonged to the Fusarium graminearum species complex. 96.4% of those isolate...

Diseases caused by crop residue-dependent pathogens have increased during the last decades in Uruguayan agriculture systems, in particular Pyrenophora tritici-repentis and Cochliobolus sativus. Consequently, we searched for the presence of fungal antagonists for these pathogens, particularly Trichoderma. Seven species of Trichoderma inhabiting soil...

Wheat occupies a special role in global food security since, in addition to providing 20% of our carbohydrates and protein, almost 25% of the global production is traded internationally. The importance of wheat for food security was recognised by the Chief Agricultural Scientists of the G20 group of countries when they endorsed the establishment of...

Fusarium head blight (FHB) and stem rust (SR) threaten the sustainability of wheat production worldwide. Fhb1 and Sr2 confer partial durable resistance to FHB and SR, respectively. Despite resistant alleles of both genes are linked in repulsion, lines with Fhb1 - Sr2 in coupling were developed at the University of Minnesota, USA. Marker-assisted ba...

Bacterial diseases affecting wheat production in Uruguay are an issue of growing concern yet remain largely uninvestigated in the region. Surveys of 61 wheat fields carried out from 2017 to 2019 yielded a regional collection of 63 strains identified by 16S rRNA gene analysis as Xanthomonas spp. A real-time PCR protocol using species-specific primer...

Eared doves (Zenaida auriculata) are responsible for substantial losses in cereal and oil crops as well as in dairy and feedlot production in the southern cone of South America. Various strategies have been shown to be effective in reducing damage at the farm scale, but in some scenarios, it is necessary to also incorporate population control metho...

Septoria tritici blotch (STB) is a major foliar disease globally, which is notorious in the fast development of fungicide resistance, making host resistance an indispensable component in mitigating STB. CIMMYT wheat line Murga is well known for its high, durable, and broad-spectrum resistance against STB infection, and the purpose of this study was...

Fusarium head blight (FHB) is the principal disease affecting wheat worldwide, decreasing grain quality, and production. This disease is mainly caused by members of the Fusarium graminearum species complex (FGSC), which have the capability to produce mycotoxins in the contaminated grains. The pathogen overwinters on crop residues (wheat straw). Und...

Las palomas torcazas (Zenaida auriculata) causan pérdidas que pueden representar hasta 50% de daño en algunos cultivos. El objetivo fue medir la aceptación de cebos contraceptivos para palomas torcazas en jaulas individuales (10 aves/tratamiento). Luego de la cuarentena y la aclimatación de las aves a la jaula, se les ofreció durante cuatro horas d...

Agriculture has experienced a strong process of changes that have led to an increase in crop diseases caused by necrotrophic pathogens. Several studies demonstrated that by managing beneficial microorganisms, it is possible to reduce the impact of plant diseases. Based on this, the objective of this study was to determine the effect of field crops...

Leaf rust (LR), caused by Puccinia triticina Ericks, is one of the most prevalent wheat diseases in Uruguay and other countries of the Southern Cone. The economic importance of the disease is clear considering that, in severe epidemics, grain yield losses of more than 50 % have been determined and that two or more fungicide applications are necessa...

Este capítulo presenta la evolución de los objetivos perseguidos en el programa de mejoramiento genético de La Estanzuela

Disease phenotyping methods used in breeding programs to characterize the level of resistance of breeding materials usually consist on visual scores (VS) of disease symptoms determined in field trials. VS are considered as high time-consuming and rely on experienced operators. Nevertheless, up to date, it is the only method that has an efficient ti...

Fusarium Head Blight (FHB) is a major constraint to barley production that substantially reduces yield and grain quality. FHB is also a major food safety concern because FHB pathogens contaminate grain with trichothecenes and other mycotoxins. DNA sequence-based analyses and in-vitro toxin assessments were used to characterize the species and trich...

Since 2014 CGIAR Research Program-WHEAT has promoted the establishment of a global network of field-based Precision Wheat Phenotyping Platforms (PWPP) to expand the existing collaborations between CIMMYT, ICARDA and National Agricultural Research System partners. The main goals are: to improve the quality of experiments conducted, data collected an...

El efecto de diferentes variables climáticas en el rendimiento de trigo y su interacción con prácticas de manejo se estimó en base a la información generada durante 21 años en ensayos de potenciales de rendimientos (García Lamothe, 1997). Los tratamientos evaluados fueron protección total con fungicidas- sin fertilización-N (PT_NF), protección tota...

Breeding for durable disease resistance in wheat is a challenging task since it is usually quantitatively inherited, thus relying on the accumulation of QTLs involved in resistance. This goal could be achieved by the use of a broad spectrum of resistance sources. Moreover, breeders usually need to test their materials in different abiotic and bioti...

To respond faster to the changing climate, evolving pathogens and to feed a global population of 9–10 billion by 2050, plant breeders are exploring more efficient crop improvement strategies. In this study, we applied novel methodology for rapid trait introgression to the European two-rowed barley cultivar Scarlett. Scarlett is widely-grown in Arge...

Ramularia leaf spot (RLS) caused by Ramularia collo-cygni (Rcc), has become one of the main constraints to barley production in Argentina and Uruguay. Grain yield losses as high as 70% have been reported in susceptible cultivars. The emergence of RLS as a major disease in the last six years has redirected coordinated research efforts to advance on...

La selección de resistencias a enfermedades efectivas y durables en el tiempo requiere un trabajo considerable, ya que muchas veces estas resistencias son de carácter cuantitativo y están relacionadas a la acumulación de diversos genes con efecto parcial (quantitative trait loci). Por ello es importante para los programas de mejoramiento contar con...

Breeding for Fusarium head blight (FHB) resistance in wheat is a challenging task since it is quantitatively inherited, thus relying on the accumulation of QTLs involved in resistance. This goal could be achieved by the use of a broad spectrum of resistance sources. Moreover, breeders usually need to test their materials in different abiotic and bi...

As an important cereal disease in humid and semi-humid areas, Fusarium head blight (FHB) has caused severe epidemics on wheat (Triticum aestivum L.) in different countries worldwide. By causing both yield loss and quality degradation, FHB presents a two-fold threat to farmers and consumers. Since the beginning of FHB research at the International...

Key message Multi-environment multi-QTL mixed models were used in a GWAS context to identify QTL for disease resistance. The use of mega-environments aided the interpretation of environment-specific and general QTL. Abstract Diseases represent a major constraint for barley (Hordeum vulgare L.) production in Latin America. Spot blotch (caused by...

Ramularia collo-cygni (Rcc) is the biotic factor responsible for the disease Ramularia leaf spot (RLS) of barley (Hordeum vulgare). Despite having been described over one hundred years ago and being considered a minor disease in some countries, the fungus is attracting interest in the scientific community as a result of the increasing number of rec...

fusariosis de la espiga (FE) de trigo (Figura 1) es una enfermedad destructiva en las regiones húmedas y sub-húmedas del mundo. En las últimas décadas ha causado pérdidas significativas en los países del Cono Sur de América del Sur y en particular en Uruguay, y representa una de las principales limitantes para la pro-ducción de trigo. La FE no sólo...

Multi-environment multi-QTL mixed models were used in a GWAS context to identify QTL for disease resistance. The use of mega-environments aided the interpretation of environment-specific and general QTL. Diseases represent a major constraint for barley (Hordeum vulgare L.) production in Latin America. Spot blotch (caused by Cochliobolus sativus), s...

Barley spot blotch (SB), caused by Cochliobolus sativus, is an important barley disease which causes extensive grain yield losses. These losses may not always correlate directly with the amount of diseased leaf area. Two barley cultivars, Quebracho (susceptible to SB) and Carumbé (with intermediate susceptibility to SB), were compared in field expe...

Members of the Fusarium graminearum species complex (FGSC) are the primary pathogens causing Fusarium head blight (FHB), Fusarium graminearum is the main pathogen of FHB and can produce various mycotoxins in wheat, in particular type B trichothecenes. This review presents information on the Fusarium species and chemotypes diversity associated to FH...

Fusarium Head Blight, mainly caused by Gibberella zeae (anamorph Fusarium graminearum) has emerged as a frequent disease in the Southern Cone of South America. In this region, the area cultivated under no-tillage has considerably increased in the last two decades. No-till generates large quantities of crop residues on the soil surface, which repres...

Members of the Fusarium graminearum species complex (FGSC) are the primary cause of Fusarium head blight (FHB) of wheat, and frequently contaminate grain with trichothecene mycotoxins that pose a serious threat to food safety and animal health. The species identity and trichothecene toxin potential of 151 FGSC isolates collected from wheat in Urugu...

Diseases represent the main constraints for barley (Hordeum vulgare L.) production in Latin America. Spot blotch (caused by Cochliobolus sativus), stripe rust (caused by Puccinia striiformis f.sp. hordei) and leaf rust (caused by Puccinia hordei) are three of the most important diseases that affect the crop in the region. Chemical control of those...

Diseases are the main problem for barley in Latin America. Spot blotch (caused by Cochliobolus sativus), stripe rust (caused by Puccinia striiformis f. sp. hordei), and leaf rust (caused by Puccinia hordei) are three of the most important diseases that attack the crop in the region. Chemical control of those diseases is both economically and enviro...

The genetic diversity of several local populations of the fungal pathogen Cochliobolus sativus, collected over 3 years from different regions of the Czech Republic, was examined using amplified fragment length polymorphism (AFLP). A high level of variability was found even among isolates from one lesion. Measures of multilocus linkage disequilibriu...

Genomic regions influencing resistance to powdery mildew [Blumeria graminis (DC.) E.O. Speer f. sp. hordei Em. Marchal] were detected in a doubled haploid (DH) barley (Hordeum vulgare L.) population derived from a cross between the breeding line ND24260 and cultivar Flagship when evaluated across four field environments in Australia and Uruguay. Si...

With 2 figures and 6 tables We studied the genetics of the resistance to leaf rust (LR) (caused by Puccinia hordei) and spot blotch (SB) (caused by Cochliobolus sativus) in barley using a doubled-haploid population derived from the cross BCD47 × Baronesse. BCD47 has low SB severity and high susceptibility to LR, while Baronesse is susceptible to SB...

A doubled haploid (DH) barley (Hordeum vulgare L.) population of 334 lines (ND24260 × Flagship) genotyped with DArT markers was used to map genes for adult plant resistance (APR) to leaf rust (Puccinia hordei Otth) under field conditions in Australia and Uruguay. The Australian barley cultivar Flagship carries an APR gene (qRphFlag) derived from th...

Grain samples from five wheat and five barley cultivars from different locations and planting dates were examined for the presence of Fusarium species. Fusarium graminearum was the primary species associated with FHB (Fusarium head blight). It comprised 76 % and 60 % of all Fusarium species isolated from wheat grains in 2001 and 2002, respectively....

Grain samples from five wheat and five barley cultivars from different locations and planting dates were examined for the presence of Fusarium species. Fusarium graminearum was the primary species associated with FHB (Fusarium head blight). It comprised 76 % and 60 % of all Fusarium species isolated from wheat grains in 2001 and 2002, respectively....

Wheat (as bran) and corn (as dry grain or fermented feed) are main ingredients of feedstuffs used in local cattle and pig farms in the South of the Buenos Aires Province (Argentina). Therefore, determining mycobiota and mycotoxins in wheat and corn is of prime importance for developing feed management techniques to optimise animal production and to...

The presence of Fusarium spp. was examined in the residues of wheat, barley, corn, sunflower, pasture, and gramineous weed species common in wheat and barley cropping systems collected from no-tillage and reduced-tillage plots from February 2001 to March 2003 in Uruguay. Gibberella zeae was recovered from residues of wheat, barley, corn, sunflower,...

Introducción El cancro de tallo del girasol es causado por el hongo Diaporthe helianthi (estado asexual: Phomopsis helianthi). La ausencia de ciclos secundarios de la enfermedad durante la estación de crecimiento del girasol determina que la cantidad de inóculo primario (ascosporas producidas en el rastrojo), la sucesión de descargas desde el rastr...

In Uruguay, a severe Fusarium epidemic in wheat in 2001 resulted in concentrations of deoxynivalenol (DON) in baked goods from 1-5 mg/kg. DONcast is a prediction model used in Canada mainly to aid fungicide spraying, but was adapted to Uruguay to help target pre-harvest regulatory and marketing actions for reducing DON contamination in wheat destin...

Cereal crop residues represent the most important inoculum source for the development of Fusarium head blight in wheat and barley. There is little information on the level of colonization or the contribution of different parts of the wheat residue to inoculum. In this study, wheat residue tissues including nodes, floral bracts (glumes, lemmas, and...

Fusarium head blight is a devastating disease of wheat and barley worldwide and has been epidemic in the South America´s Southern cone for the past decade. Currently, available control measures are only partially effective and biological control could be an additional tool in an integrative approach to manage Fusarium head blight. In Uruguay, since...

In September 2003, leaves exhibiting spot-type lesions similar to those produced by Cochliobolus sativus Drechs. ex Dastur were widely observed in six commercial barley crops of cvs. Nortena Dayman, Nortena Carumbe, and MUSA 936 in Soriano and Rio Negro provinces, the main barley production region in western Uruguay. Spot lesions were tan to dark b...

Survival and inoculum production of Gibberella zeae (Schwein.) Petch (anamorph Fusarium graminearum (Schwabe)), the causal agent of Fusarium head blight of wheat and barley, was related to the rate of wheat (Triticum aestivum L.) residue decomposition. Infested wheat residue, comprising intact nodes, internodes, and leaf sheaths, was placed in fibe...

We would like to gratefully acknowledge contributions of the following companies and organizations for partial sponsorship: MICHIGAN STATE U N I V E R S I T Y ©Copywrite1998 by the individual authors.

Introducción Los cereales de invierno integran las rotaciones agrícolas más tradiciones del país siendo la cebada y en especial el trigo los de mayor área de siembra, con un 85 % de su área en siembra directa (SD). Para estos cereales como para cualquier cultivo, el potasio (K) es uno de los 4 nutrientes que se requieren en una cantidad similar a l...

Diseases are the main problem for barley in Latin America. Spot blotch (caused by Cochliobolus sativus), stripe rust (caused by Puccinia striiformis f.sp. hordei) and leaf rust (caused by Puccinia hordei) are three of the most important diseases that attack the crop in the region. Chemical control of those diseases is both economically and environm...