A comparative analysis of chromosome pairing at metaphase I in interspecific hybrids between durum wheat (Triticum turgidum L.) and the most widespread Aegilops species.

Homoeologous metaphase I (MI) associations in hybrids between durum wheat and its wild allotetraploid relatives Aegilops neglecta, Ae. triuncialis and Ae. ventricosa have been characterized by a genomic in situ hybridization procedure that allows simultaneous discrimination of A, B and wild species genomes. Earlier results in equivalent hybrids with the wild species Ae. cylindrica and Ae. geniculata have also been considered to comparatively assay the MI pairing pattern of the durum wheat × Aegilops interspecific combinations more likely to occur in nature. The general picture can be drawn as follows. A and B wheat genomes pair with each other less than the 2 wild constituent genomes do in any of the hybrid combinations examined. Interspecific wheat-wild associations account for 60–70% of total MI pairing in all hybrids, except in that derived from Ae. triuncialis, but the A genome is always the wheat partner most frequently involved in MI pairing with the wild homoeologues. Hybrids with Ae. cylindrica, Ae. geniculata and Ae. ventricosa showed similar reduced levels of MI association and virtually identical MI pairing patterns. However, certain recurrent differences were found when the pattern of homoeologous pairing of hybrids from either Ae. triuncialis or Ae. neglecta was contrasted to that observed in the other durum wheat hybrid combinations. In the former case, a remarkable preferential pairing between the wild species constituent genomes Ut and Ct seems to be the reason, whereas a general promotion of homoeologous pairing, qualitatively similar to that observed under the effect of the ph1c mutation, appears to occur in the hybrid with Ae. neglecta. It is further discussed whether the results reported here can be extrapolated to the corresponding bread wheat hybrid combination

Thermographic imaging: assessment of drought and heat tolerance in Spanish germplasm of Brachypodium distachyon.

The annual grass Brachypodium distachyon has been recently recognized as the model plant for functional genomics of temperate grasses, including cereals of economic relevance like wheat and barley. Sixty-two lines of B. distachyon were assessed for response to drought stress and heat tolerance. All these lines, except the reference genotype BD21, derive from specimens collected in 32 distinct locations of the Iberian Peninsula, covering a wide range of geo- climatic conditions. Sixteen lines of Brachypodium hybridum, an allotetraploid closely related to B. distachyon were used as reference of abiotic-stress well-adapted genotypes. Drought tolerance was assessed in a green-house trial. At the rosette-stage, no irrigation was applied to treated plants whereas their replicates at the control were maintained well watered during all the experiment. Thermographic images of treated and control plants were taken after 2 and 3 weeks of drought treatment, when stressed plants showed medium and extreme wilting symptoms. The mean leaf temperature of stressed (LTs) and control (LTc) plants was estimated based upon thermographic records from selected pixels (183 per image) that strictly correspond to leaf tissue. The response to drought was based on the analysis of two parameters: LTs and the thermal difference (TD) between stressed and control plants (LTs – LTc). The response to heat stress was based on LTc. Comparison of the mean values of these parameters showed that: 1) Genotypes better adapted to drought (B. hybridum lines) presented a higher LTs and TD than B. distachyon lines. 2) Under high temperature conditions, watered plants of B. hybridum lines maintained lower LTc than those of B. distachyon. Those results suggest that in these species adaptation to drought is linked to a more efficient stomata regulation: under water stress stomata are closed, increasing foliar temperature but also water use efficiency by reducing transpiration. With high temperature and water availability the results are less definite, but still seems that opening stomata allow plants to increase transpiration and therefore to diminish foliar temperature

Karyotype characterization of wheat breeding lines carrying resistance genes from Aegilops ventricosa

We have used in situ hybridization combining genomic and repeated DNA fluorescent probes to determine the karyotype composition of two bread wheat introgression lines: H-93-33, which carries the gene H27 for resistance to the Hessian fly M. destructor (Delibes et al. 1997); and H-93-8, carrying the gene Cre2 which confers resistance to the cereal cyst nematode H. avenae (Delibes et al. 1993). Both introgression lines had been derived from an earlier cross between T. aestivum subsp. aestivum (2n=42; genome composition AABBDD) and a semi-fertile hybrid between T. turgidum subsp. turgidum (2n=28; genome composition AABB) and the wild grass Ae. ventricosa (2n=28; genome constitution DvDvN¬vNv). We also have examined several resistant advanced lines that were obtained from H-93-33 (lines ID-2151, ID-2193, Ma-1612-a and Ma-1612-b) or H-93-8 (line ID-2150) after 3 to 5 backcrosses with commercial wheats

Neutral molecular markers support common origin of aluminium tolerance in three congeneric grass species growing in acidic soils

Relaciones genéticas entre accesiones de Brachypodium tolerantes y susceptibles a aluminio

Análisis comparativo del potencial de siete variedades de triticale para usos agroenergéticos.

Se han realizado ensayos de campo durante 2008 y 2009 para evaluar la producción de biomasa seca y de los principales componentes celulósicos de la biomasa, y el rendimiento en grano de 7 variedades de triticale y 5 variedades de otros cereales (centeno, avena forrajera y trigo blando). Los centenos analizados, en particular la variedad híbrida ‘Picasso’, han sido los materiales más productivos, tanto en lo que respecta a su posible rendimiento energético, como en su condición de cereal para grano. No obstante, los triticales ‘Forricale’ y ‘Misionero’ han mostrado un buen potencial como cultivo agroenergé- tico, especialmente en condiciones climatológicas adversas. También destacan en cuanto a su posible utilización como variedades de doble uso: biocombustible y cereal-grano

Use of thermographic imaging to screen for drought-tolerant genotypes in Brachypodium distachyon

Thermal imaging has been used to evaluate the response to drought and warm temperatures in a collection of Brachypodium distachyon lines adapted to varied environmental conditions. Thermographic records were able to separate lines from contrasting rainfall regimes. Genotypes from dryer environments showed warmer leaves under water deficit, which suggested that decreased evapotranspiration was related to a more intense stomatal closure. When irrigated and under high temperature conditions, drought-adapted lines showed cooler leaves than lines from wetter zones. The consistent, inverse thermographic response of lines to water stress and heat validates the reliability of this method to assess drought tolerance in this model cereal. It additionally supports the hypothesis that stomatal-based mechanisms are involved in natural variation for drought tolerance in Brachypodium. The study further suggests that these mechanisms are not constitutive but likely related to a more efficient closing response to avoid dehydration in adapted genotypes. Higher leaf temperature under water deficit seems a dependable criterion of drought tolerance, not only in B. distachyon but also in the main cereal crops and related grasses where thermography can facilitate high-throughput preliminary screening of tolerant materials

Análisis de la diversidad para proteínas de endospermo en los citotipos 2N=10 y 2N=30 de Brachipodium

Se han analizado mediante electroforesis las proteínas del endospermo de 38 poblaciones españolas de brachypodium, correspondientes a los citotipos de 10 y 30 cromosomas. En total, se han identificado 40 bandas de proteínas diferentes, ninguna de las cuales ha resultado ser específica de uno de los dos citotipos. Se ha encontrado una alta variabilidad intra- e interpoblacional, siendo las poblaciones de 30 cromosomas las que muestran el mayor grado de diversidad genétic

Effects of the 4N(v) chromosome from Aegilops ventricosa on agronomic and quality traits in bread wheat

Advanced wheat lines carrying the Hessian fly resistance gene H27 were obtained by backcrossing the wheat/Aegilops ventricosa introgression line, H-93-33, to commercial wheat cultivars as recurrent parents. The Acph-N v 1 marker linked to the gene H27 on the 4Nv chromosome of this line was used for marker assisted selection. Advanced lines were evaluated for Hessian fly resistance in field and growth chamber tests, and for other agronomic traits during several crop seasons at different localities of Spain. The hessian fly resistance levels of lines carrying the 4Nv chromosome introgression (4D/4Nv substitution and recombination lines that previously were classified by in situ hybridisation) were high, but always lower than that of their Ae. ventricosa progenitor. Introgression lines had higher grain yields in infested field trials than those without the 4Nv chromosome and their susceptible parents, but lower grain yields under high yield potential conditions. The 4Nv introgression was also associated with later heading, and lower tiller and grain numbers/m2 . In addition, it was associated with longer and more lax spikes, and higher values of grain weight and grain protein content. However, the glutenin and gliadin expression, as well as the bread-making performance, were similar to those of their recurrent parent

Calidad semolera y nuevas variantes alélicas prolaminas en variedades indígenas españolas d trigo duro (Triticum Turgidum L. Tell.)

Las prolaminas son las principales proteínas del endospermo de los trigos panaderos que están relacionadas con la calidad panadera. El objetivo de este trabajo es caracterizar gluteninas LMW según la nomenclatura de Liu et al y relacionarlas con la fuerza panadera

Ampliación de la variabilidad genética de la colección de Aegilops conservada en ell CRF-INIA y caracterización molecular de las especies Neglecta y Geniculata

En este trabajo se expone el doble objetivo de incrementar la representación de la variabilidad genética de las especies Ae. geniculata, Ae. ventricosa, Ae. neglecta, y Ae. triuncialis que han evolucionado en España, y diferenciar correctamente las especies neglecta y geniculata