Efecto de la fertilizacion nitrogenada y azufrada sobre el rendimiento en grano y sus componentes en <i>Triticum aestivum</i> L.

El azufre es un elemento esencial para la nutrición de las plantas y afecta tanto el rendi­miento en grano, como su calidad. La cantidad de azufre orgánico en el grano de trigo representa un 80-95% del azufre total del cultivo en madurez (Byers et al, 1987). Este nutriente no ha sido considerado de importancia en el trigo, posiblemente porque los fertilizantes comunmente usados en este cultivo (superfosfatos simple y sulfato de amonio) pro­veen un suministro adecuado para el normal crecimiento del mismo. Estudios realizados en Australia y Gran Bretaña, indican que la sustitución de estos ferti­lizantes por altas dosis de fertilizantes nitrogena­dos puros (urea y amoníaco anhidro), ha puesto en evidencia deficiencias de este nutriente en cultivos de trigo (Archer, 1974; Byers & Bolton, 1979; Spencer & Freney, 1980; Randall et al, 1981; Timms et al, 1981). En nuestro país se ha registrado un incre­mento en el uso de fertilizantes nitrogenados, principalmente urea, aplicados en altas dosis. De acuerdo con lo expuesto precedentemente po­dría esperarse entonces, que en suelos con bajo contenido de azufre se observe una respuesta a la aplicación de este elemento.Facultad de Ciencias Agrarias y Forestale

Polymorphism at High Molecular Weight Glutenin Subunits and Morphological Diversity of Aegilops geniculata Roth Collected in Algeria

A collection of 35 accessions of the tetraploid wild wheat Aegilops geniculata Roth (MM, UU) sampled in northern Algeria was evaluated for morphological and biochemical variability. Morphological and ecological analyses based on morphological traits and bioclimatic parameters, respectively, were assessed using principal component analysis (PCA). Accessions were differentiated by width characters, namely spike’s width, and a weak relationship between morphological traits and ecological parameters was found. Polymorphism of high molecular weight (HMW) glutenin subunits was carried on by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Among accessions analyzed, 27 alleles were identified at the two loci Glu-M1 and Glu-U1: resulting in twenty-nine patterns and a nomenclature was proposed. Two alleles at the Glu-U1 locus expressed a new subunit with a slightly slower mobility than subunit 8. These results provide new information regarding the genetic variability of HMW glutenin subunits, as well as their usefulness in cultivated wheat quality improvement

Identification of Gliadin Bands 42 and 45 in <i>Triticum durum</i> Def.

Se evaluaron por electroforesis en gel de poliacrilamida variedades y líneas de mejoramiento de trigo candeal, estableciendo la presencia o ausencia de las bandas 45 y 42, relacionadas con la fuerza del gluten. Para ello se utilizó la técnica de electroforesis en gel de poliacrilamida a pH 3,1. Las variedades Marquis, Wascana y los biotipos A y B de Duramba se utilizaron como referencia para el estudio de la Movilidad Relativa de las bandas. Todas las variedades presentaron la banda 45, con excepción de Thomas Ventanía, que presentó la 42.El objetivo del trabajo fue evaluar dicha técnica y su utilidad en la selección de cultivares sobre la base de su calidad industrial.Lines and varieties of durum wheat were evaluated in order to determine the presence or absence of 45 and 42 bands which are related with gluten strength. For this purpose polyacrylamide gel electrophoresis at pH 3,1 was used. Varieties Marquis, Wascana and biotypes A and B of Duramba were used as references for the study of relative bands mobility. All varieties presented band 45, excepting Thomas Ventanía which presented band 42. The aim of this work was to evaluate this technique to verify if it is useful as a selection criteria in breeding for industrial quality.Facultad de Ciencias Agrarias y Forestale

Identification of Gliadin Bands 42 and 45 in <i>Triticum durum</i> Def.

Se evaluaron por electroforesis en gel de poliacrilamida variedades y líneas de mejoramiento de trigo candeal, estableciendo la presencia o ausencia de las bandas 45 y 42, relacionadas con la fuerza del gluten. Para ello se utilizó la técnica de electroforesis en gel de poliacrilamida a pH 3,1. Las variedades Marquis, Wascana y los biotipos A y B de Duramba se utilizaron como referencia para el estudio de la Movilidad Relativa de las bandas. Todas las variedades presentaron la banda 45, con excepción de Thomas Ventanía, que presentó la 42.El objetivo del trabajo fue evaluar dicha técnica y su utilidad en la selección de cultivares sobre la base de su calidad industrial.Lines and varieties of durum wheat were evaluated in order to determine the presence or absence of 45 and 42 bands which are related with gluten strength. For this purpose polyacrylamide gel electrophoresis at pH 3,1 was used. Varieties Marquis, Wascana and biotypes A and B of Duramba were used as references for the study of relative bands mobility. All varieties presented band 45, excepting Thomas Ventanía which presented band 42. The aim of this work was to evaluate this technique to verify if it is useful as a selection criteria in breeding for industrial quality.Facultad de Ciencias Agrarias y Forestale

Identification of SNPs and development of allele-specific PCR markers for γ-gliadin alleles in Triticum aestivum

The coding regions of 28 entries of hexaploid wheat γ-gliadin genes, gene fragments or pseudogenes in GenBank were used for nucleotide alignment. These sequences could be divided into nine subgroups based on nucleotide variation. The chromosomal locations of five of the seven unassigned subgroups were identified through subgroup-specific polymerase chain reactions (PCR) using Chinese Spring group-1 nulli-tetrasomic lines. Multiple single nucleotide polymorphisms (SNPs) and small insertions/deletions were identified in each subgroup. With further mining from wheat expressed sequence tag databases and targeted DNA sequencing, two SNPs were confirmed and one SNP was discovered for genes at the Gli-A1, Gli-B1 and Gli-D1 loci. A modified allele-specific PCR procedure for assaying SNPs was used to generate dominant DNA markers based on these three SNPs. For each of these three SNPs, two allele-specific primer sets were used to test Chinese Spring and 52 commercial Australian wheat varieties representing a range of low-molecular-weight (LMW) alleles. PCR results indicated that all were positive with one of the primer sets and negative with the other, with the exception of three varieties containing the 1BL/1RS chromosomal translocation that were negative for both. Furthermore, markers GliA1.1, GliB1.1 and GliD1.1 were found to be correlated with Glu-A3 a, b or c, Glu-B3 b, c, d or e and Glu-D3 a, b or e LMW glutenin alleles, respectively. Markers GliA1.2, GliB1.2 and GliD1.2 were found to be correlated with the Glu-A3 d or e, Glu-B3 a, g or h and Glu-D3 c alleles, respectively. These results indicated that the γ-gliadin SNP markers could be used for detecting linked LMW glutenin subunit alleles that are important in determining the quality attributes of wheat products