Transfer of a major dominant gene for resistance to eyespot disease from a wild grass to hexaploid wheat

Eyespot disease, caused by the fungus Pseudocercosporella herpotrichoides, is responsible for considerable lodging and reductions of yield in extensive areas of wheat cultivation in North and South America, Europe, New Zealand, Australia and Africa1. The level of resistance of wheat cultivars is too low, even among the less susceptible ones (that is, Cappelle Desprez and Cerco) and no genes for resistance have to date been characterized in any species. Sprague2 found a high level of resistance to this disease in the wild grass Aegilops ventricosa and several workers have attempted its transfer to cultivated wheat with only partial success3−5. We report here a major dominant gene for resistance, which has been transferred from tetraploid Ae. ventricosa (genomes DvDvMvMv) to hexaploid wheat, Triticum aestivum (AABBDD), using tetraploid wheat, Triticum turgidum (AABB), as a 'bridge' species

Resistance to eyespot (Pseudocercosporella herpotricoides) and distribution of biochemical markers in hexaploid lines derived from double cross (Triticum turgidum x Aegilops ventricosa) x T. aestivum

There are not good intraspecific sources of resistance to the eyespot disea se of wheat, aaused by Cercosporella herpotrichoides Fvon . The -ínterspecifia transfer of genes for resistanoe from Aegitops ventricosa into hexaploid wheat has been only partially achieved, because the degree of resistanoe attained is not as high as that of the donor. We report here on the transfer of resistanoe in a double oross (Triticum turgidum var. rubroatrwv H-1-1 x Ae.ventricosa AP-D x T.aestivum cv. Almatense H-10-15. The high level of resistanoe in a high proportion of the lines strongly suggests a simple genetic control for this oharacter (possibly by one major gene). The gene(s) responsible for resistanoe in the selected lines must be associa ted with the D genome of Aegilops ventricosa on the basis of a detailed study of the distribution of biochemioal markers in the H-93 lines. These results do not exelude that genes with similar effeets might be looated in the M° genome

Biochemical markers associated with two Mv chromosomes from Aegilops ventricosa in wheat-Aegilops addition lines

The distribution of three biochemical markers, U-1, CM-4 and Aphv-a, -b, among wheat-Aegilops addition lines carrying Mv chromosomes from Aegilops ventricosa (genomes DvMv) has been investigated. Addition lines which had been previously grouped together on the basis of common non-biochemical characters carried marker U-1, a protein component from the 2M urea extract. The added chromosome, in the appropriate genetic background, seems to confer a high level of resistance to the eyespot disease, caused by the fungus Cercosporella herpotrichoides. The other two markers were concomitantly associated with another similarly formed group of addition lines. Both CM-4, a protein component from the chloroform:methanol extract, and Aphv-a, -b, alkaline phosphate isozymes, have been previously shown to be associated with homoeologous chromosome group 4, which suggests that the added chromosome in the second group of addition lines is 4Mv

Eyespot resistance gene Pch-1 in H-93 wheat lines. Evidence of linkage to markers of chromosome group 7 and resolution from the endopeptídase locus Ep-Dlb

Gene Pch1, which confers resistance to eyespot disease (Pseudocercosporella herpotrichoides Fron), has been located on chromosome 7D in the H-93 wheat-Aegilops ventricosa transfer lines using isozyme markers and DNA probes corresponding to group 7 chromosomes. Previous experiments had failed to ascertain this location. The lack of segregation of the resistance trait in progeny from reciprocal crosses between lines H-93-70 and VPM1 indicates that their respective resistance factors are allelic. Line H-93-51 carries the endopeptidase allele Ep-D1b but is susceptible to eyespot, which indicates that resistance to eyespot is not a product of the Ep-D locus, as had been proposed in a previous hypohesi

Factores ambientales condicionantes de la presencia de la lagartija de Carbonell Podarcis carbonelli (Pérez-Mellado, 1981) en la comarca de Doñana

The Carbonell lizard (Podarcis carbonelli) is an Iberian endemism. The region of Doñana is its southernmost and more isolated stronghold. We used logistic regressions to investigate the factors conditioning the presence of this lizard in Doñana. All selected models retained the distance to the coast as the main variable. This variable is related with less humidity and more continental climatic conditions, including more extreme temperatures, when further from the coast. This climatic factor was observed both spatially and temporarily, with adult lizards drastically reducing their activity both in winter and in summer. We observed juveniles from June to January, with a maximum in September. Scrubland management was another important environmental factor affecting the presence of lizards. The probability of finding this species was higher where the scrubland was partially cleared, and lower in areas with a high plant cover (hygrophytic scrubland) or in areas with sparse vegetation (dune scrubland), probably due to a lower amount of incident light and less protection when moving between refuges, respectively.La lagartija de Carbonell es un endemismo ibérico que encuentra en la comarca de Doñana el reducto más meridional y aislado de su área de distribución. Mediante el uso de regresiones logísticas se ha intentado conocer qué factores condicionan la presencia de la lagartija de Carbonell en Doñana. La variable principal de los distintos modelos fue la distancia a la costa. Ésta se relaciona con un menor grado de humedad y una mayor continentalidad del clima, con temperaturas más extremas, a medida que nos alejamos del mar. Este condicionante climático se ha observado tanto espacial como temporalmente, reduciéndose drásticamente la actividad de los animales adultos en verano e invierno. Los juveniles se observan desde junio a enero con un máximo en septiembre. Otro de los factores importantes ha resultado ser la gestión del matorral. Se ha observado una mayor probabilidad de encontrar la lagartija de Carbonell en zonas en las que el matorral ha sido parcialmente clareado, ya que evita los lugares con elevadas densidades de plantas (matorral hidrofílico), que reducirían el paso de la luz, o con una densidad muy baja (matorral de las dunas), que no permitiría el tránsito seguro entre refugios

Biochemical and cytological characterization of wheat/Aegilops ventricosa addition and transfer lines carrying chromosome 4MV

The gene encoding a variant of alcohol dehydrogenase, Adh-, has been found to be associated with the chromosome of the Mv genome which is present in type 9 wheat/Aegilops ventricosa addition line, to which the genes for protein CM-4 and for a phosphatase variant, Aph-v, had been previously assigned. Transfer line H-93-33, which has 42 chromosomes and has been derived from the cross (Triticum turgidum x Ae. ventricosa) x T. aestivum, carries genes encoding all three biochemical markers. Linkage between these genes has been demonstrated by analysis of individual kernels of the F2 (H-93-33 x T. aestivum cv. Almatense H-10-15). A study of the hybrids of line H-93-33 with T. aestivum H-10-15 and with the 4DS ditelosomic line has confirmed that, as suspected, the linkage group corresponds to chromosome 4Mv from Ae. ventricosa. Additionally, it has been found that the previously reported resistance of line H-93-33 to powdery mildew (Erysiphe graminis) is also linked to the biochemical markers; this indicates that either the gene responsible for it is different from that in lines H-93-8 and H-93-35, or that a translocation between two different Mv chromosomes has occurred in line H-93-33

Un puñal de la Edad del Bronce hallado en El Mirón, Avila.

89 Jan.-Dez. 1979, p. 327-331

Peroxidase expression in a cereal cyst nematode (Heterodera avenae) resistant hexaploid wheat line.

The incompatible interaction between plant and pathogen is often determined by the hypersensitive reaction (HR). This response is associated with accumulation of reactive oxygen species (ROS), which results in adverse growth conditions for pathogens. Two major mechanisms involving either NADPH oxidases or peroxidases have been proposed for generation of ROS. Peroxidases (PER, EC 1.11.1.7), present in all land plants, are members of a large multigenic family with high number of isoforms involved in a broad range of physiological processes. PER genes, which are expressed in nematode feeding sites, have been identified in several plant species (Zacheo et al. 1997). A strong correlation between HR and PER activities at four and seven days post nematode infection, was detected in roots of wheat lines carrying Cre2, Cre5 (from Ae. ventricosa) or Cre7 (from Ae. triuncialis) Heterodera avenae resistance genes (Andrés et al. 2001; Montes et al. 2003, 2004). We have studied changes in root of peroxidase mRNAs levels after infection by H. avenae of a wheat/Ae. ven¬tricosa introgression line (H-93-8) carrying Cre2 (Delibes et al. 1993). We also report and classify the predicted protein sequences derived from complete peroxidase transcripts

El relleno de taladros producidos por la extracción de probetas-testigo y su influencia en la resistencia de los pilares de hormigón armado

Three series of tests on a total number of 24 reinforced concrete columns were performed by the authors at Instituto Técnico de Materiales y Construcciones (INTEMAC) with the purpose of studying the influence of different kinds of bore fills from drilled core test-pieces made in the columns. The conclusions obtained make it possible to claim that column strength will be completely recovered either by coating bore surfaces with resin followed by concrete filling or by filling of bore with concrete and expansion agent. The increase in column load while concrete filling is still young does not affect its final load bearing capacity. Core drilling and filling of columns under an applied load of 50% of ultimate load does not affect final strength either.Los autores han realizado en el Instituto Técnico de Materiales y Construcciones CINTEMAC) tres series de ensayos con un total de 24 pilares de hormigón armado, estudiando la influencia de distintos tipos de relleno de los taladros de probetas-testigo efectuados en ellos. Las conclusiones obtenidas permiten establecer que la resistencia de los pilares se recupera íntegramente al rellenar, tanto con tratamiento de resina en las paredes del taladro y relleno de hormigón, como si el relleno se realiza con hormigón y un agente expansivo. El hecho de que se incremente la carga del pilar, cuando el hormigón de relleno es joven, no altera fa capacidad final de la pieza. Tampoco el que el taladro y posterior relleno se realice en pilares sometidos al 50% de su carga de rotura afecta a la resistencia final

Provision of artificial warrens as a means to enhance native wild rabbit populations: what type of warren and where should they be sited?

In Spain, wild rabbits are essential for some highly endangered species, and, therefore, many actions have been undertaken to increase their populations. In the present study, artificial warrens are provided as a means to increase shelter for native wild rabbit populations in a given area. We evaluate the use of three types of warrens by rabbits and the effect on that use of five habitat characteristics at two spatial scales (500 × 500-m grids and 25-m plots). To evaluate that use, we identified pre-established signs at the entrances to each warren, and based on this, we calculated occupancy rate and activity. Our results indicate that rabbit abundance within a grid is the only variable which simultaneously explains both the greater occupancy and the higher activity in the artificial warrens located in that grid. Some 73.2% of the grids showed signs of rabbit use at the time of the evaluation. However, the pre-existing rabbit populations within the grids were not quantified and, hence, we cannot state that the warrens contributed to an increase in the rabbit abundance. Regarding the habitat, our results reveal that warrens should be situated in grids with food coverage of less than 50%, while the use of each individual refuge is greater where food availability in the immediate surroundings is at least 20% and shelter at least 50%. The tube warrens showed significantly greater rabbit use than the other types while there was little difference between the stone and pallet warrens in terms of use