a b s t r a c tWheat consumption is growing, with processors asking for wheat-based products showing better and more consistent quality. Genotype, environment and their interaction (G Â E) play an important role in the final expression of quality attributes. An international research consortium was developed in order to evaluate the magnitude of genotype, environment and G Â E effects on wheat quality of cultivars developed for different agro-ecological zones in Latin America. Genotypes released in Argentina, Brazil, Chile, Mexico, Paraguay and Uruguay, were cultivated in twenty different environments within the participating countries. Each environment was characterized for cultural practices, soil type and climatic conditions. Grain yield and analyses of test weight, protein, ash, gluten, Alveograph, Farinograph, Falling Number, SDS sedimentation and flour color were determined. Allelic variations of puroindolines and glutenins were determined in all the genotypes evaluated. Both puroindoline and gluten protein alleles corresponded to genotypes possessing medium to very good bread making quality. Large variability for most quality attributes evaluated was observed, with wider ranges in quality parameters across environments than among genotypes; even for parameters known to be largely determined by genotype. The importance of growing environment on grain quality was proved, suggesting that breeders' quality objectives should be adapted to the targeted environments.

Cereal Chem. 88(2):130-136Nowadays in Argentina, cookies, crackers, and cakes are made of flour obtained from bread wheat with additives or enzymes that decrease the gluten strength but increase production costs. The present research work aims to study the relationship between flour physicochemical composition (particle size average [PSA], protein, damaged starch [DS], water soluble pentosans [WSP], total pentosans [TP], and gluten), alkaline water retention capacities behavior, solvent retention capacities profile (SRC) and cookie-making performance in a set of 51 adapted soft wheat lines with diverse origin to identify better flour parameters for predicting cookie quality. Cookie factor (CF) values were 5.06-7.56. High and significant negative correlations between sucrose SRC (-0.68), water SRC (-0.65), carbonate SRC (-0.59), and CF were found, followed by lactic SRC that presented a low negative but significant correlation (r = -0.35).The flour components DS (r = -0.67), WSP (r = -0.49), and TP (r = -0.4) were negatively associated to CF. PSA showed a negative correlation with CF (r = -0.43). Protein and gluten were the flour components that affected cookie hardness, but no significant correlation were found with pentosan or DS content. A prediction equation for CF was developed. Sucrose SRC, PSA, and DS could be used to predict 68% of the variation in cookie diameter. The cluster analysis was conducted to assess differences in flour quality parameters among genotypes based on CF. Clusters 1 and 4 were typified by lower CF (5.70 and 5.23, respectively), higher DS, pentosan content, and SRC values. Cluster 2 with a relative good CF (6.47) and Cluster 3 with the best cookie quality, high CF (7.32) and low firmness, and the lowest DS, TP, WSP content, and sucrose SRC values.

Leaf rust, caused by Puccinia triticina Eriks. is a common and widespread disease of bread wheat (Triticum aestivum L.), in Argentina. Host resistance is the most economical, effective and ecologically sustainable method of controlling the disease. Gene postulation helps to determine leaf rust resistance genes (Lr genes) that may be present in a large group of wheat germplasm. Additionally presence of Lr genes can be determined using associated molecular markers. The objective of this study was to identify Lr genes that condition leaf rust resistance in 66 wheat cultivars from Argentina. Twenty four differential lines with individual known leaf rust resistance genes were tested with 17 different pathotypes of leaf rust collected from Argentina. Leaf rust infection types produced on seedling plants of the 66 local cultivars were compared with the infection types produced by the same pathotypes on Lr differentials to postulate which seedling leaf rust genes were present. Presence of Lr9, Presence of Lr21, Lr25, Lr29, and Lr47 could not be determined with the seventeen pathotypes used in the study because all were avirulent to these genes. Eleven cultivars (16.7%) were resistant to all pathotypes used in the study and the remaining 55 (83.3%) showed virulent reaction against one or more local pathotypes. Cultivars with seedling resistance gene combinations including Lr16 or single genes Lr47 (detected with molecular marker), Lr19 and Lr41, showed high levels of resistance against all pathotypes or most of them. On the opposite side, cultivars with seedling resistance genes Lr1, Lr3a, Lr3a + Lr24, Lr10, Lr3a + Lr10, Lr3a + Lr10 + Lr24 showed the highest number of virulent reactions against local pathotypes. Occurrence of adult plant resistance genes Lr34, Lr35 and Lr37 in local germplasm was evaluated using specific molecular markers confirming presence of Lr34 and Lr37. Our data suggest that combinations including seedling resistance genes like Lr16, Lr47, Lr19, Lr41, Lr21, Lr25 and Lr29, with adult plant resistance genes like Lr34, SV2, Lr46 will probably provide durable and effective resistance to leaf rust in the region.

With 3 figures and 1 table Abstract This work describes a novel null Wx‐A1 allele detected in one cultivar and two breeding lines from a collection of 48 durum wheats from Argentina. The electrophoretic patterns of waxy proteins showed 45 accessions displaying Wx‐A1 and Wx‐B1 proteins and three accessions that lacked the Wx‐A1 protein. Partial sequence of the Wx‐A1 gene obtained from the three lines lacking the Wx‐A1 protein showed a 1‐bp deletion in exon 6 that produces a frameshift and a premature stop codon in the gene sequence. In addition, a PCR‐RFLP marker suitable to detect the null Wx‐A1 allele in segregating populations is described.

ar).Abbreviations: A-PAGE, acid polyacrylamide gel electrophoresis; BC, backcross; MAS, marker-assisted selection; MLT, multilocation testing; RYT, regional yield trials; SDS-PAGE, sodium dodecyl sulphate polyacrylamide gel electrophoresis.is adapted to nonirrigated production areas in the humid plains from southern Córdoba and Santa Fé, Buenos Aires, and La Pampa Provinces from Argentina. BIO refers to Bioceres SA, a private company that has exclusivity in the commercialization of the cultivar, INTA refers to the National Institute of Agricultural Technology, which developed the cultivar, and 2004 is the serial number of midmaturity cultivars released under this agreement. The interstitial translocation line T7AS-7S#1-7S.7AL carrying Lr47 from T. speltoides (Tausch) Green. was originally transferred to bread wheat by irradiating hybrid seed (CI15092/T. speltoides//'Fletcher'/3/5*Centurk) with fast neutrons (Wells et al., 1982). Interstitial segments of chromosome 7S#1 were transferred to chromosome 7A of hexaploid wheat using the ph1b mutation (Lukaszewski, 1995). The interstitial translocations were backcrossed into the hard white spring variety Pavon 76 (PI 519847), and plants homozygous for the interstitial translocation were released as germplasm PI 603918 (Lukaszewski et al., 2000). The T. speltoides segment is generally transferred as a single linkage block (Helguera et al., 2000). In previous studies, resistance gene Lr47 was shown to be effective against leaf rust races in fi eld trials at University of Methods

RESUMENEl cultivo de trigo (Triticum aestivum L.), es el cereal de invierno de mayor importancia económica en Argentina. Su producción se halla limitada por diversos factores, entre ellos las enfermedades virales. El objetivo del presente trabajo fue identificar y caracterizar biológicamente una enfermedad viral detectada recientemente en el cultivo de trigo en Argentina, que ha presentado elevada incidencia en los últimos años. Para ello, se recolectaron plantas con síntomas en localidades de: Miramar y Balcarce (Buenos Aires), Río Cuarto, Rosales y Marcos Juárez (Córdoba), Paraná (Entre Ríos) y General Pico (La Pampa) de la región triguera Argentina. Las muestras fueron caracterizadas a través de: microscopia electrónica ("leaf-dip" y cortes ultrafinos), serología (con antisueros para diferentes virosis del trigo por DAS-ELISA y ELISA indirecto), transmisión mecánica, por semilla y por vectores (delfácidos), rango de hospedantes diferenciales y susceptibilidad diferencial de diferentes cultivares de trigo en infecciones naturales. Los resultados obtenidos evidenciaron que esta nueva enfermedad es causada por el Barley yellow striate mosaic virus (BYSMV) (Rhabdoviridae-Cytorhabdovirus), un virus ampliamente distribuido a nivel mundial y que representa un riesgo potencial para otros cultivos como cebada, avena y triticale. Este trabajo representa el primer reporte del BYSMV en Argentina. Palabras clave: Cytorhabdovirus, Delphacidae, Gramineae. ABSTRACT Identification and biological characterization of Barley yellow striate mosaic virus (BYSMV): A new wheat disease in ArgentinaWheat (Triticum aestivum L.) is the most important winter grain in Argentina. Its production is limited by several factors, including viral diseases. The aim of this study was to identify and characterize a recently detected disease of wheat crops in Argentina. Symptomatic plants were collected from different locations from the wheat production area, Miramar and Balcarce (Buenos Aires), Río Cuarto, Rosales and Marcos Juarez (Córdoba), Paraná (Entre Ríos) and General Pico (La Pampa). Samples were characterized by: electron microscopy (leaf-dip and ultrathin sections), serological tests (with antiserum reacting against different wheat viruses by DAS-ELISA and indirect ELISA), mechanical, seed and vector transmission assays, differential host range, and susceptibility of different wheat cultivars in natural infections. The results showed that this new disease is caused by Barley yellow striate mosaic virus (BYSMV) (RhabdoviridaeCytorhabdovirus), a widely distributed virus that can be transmitted to other crops such as barley, oat and triticale. This work represents the first report of BYSMV in Argentina.

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