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( Alcázar et al., 2010 ; Gill & Tuteja, 2010 ; Shi et al., 2010 ). It has been demonstrated that PAs are also involved in the tolerance of plants to abiotic stresses because the accumulation of PAs is enhanced under stressful conditions ( Fariduddin et

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amino acids has been considered as a promising approach to improve the growth of crop plants ( Teixeira et al., 2017 ). Under abiotic stresses, foliar application of N -acetyle-cysteine (Cys) alleviated the adverse effects of salt stress ( Genisel et

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silicate on Fusarium sulphureum and its effect on dry rot of potato tubers . J. Food Sci. 74 , M213 – M218 . Liang , Y. , Sun , W. , Zhu , Y. G. and Christie , P. ( 2007 ): Mechanisms of silicon-mediated alleviation of abiotic stresses in

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Mackill, D.J. 2006. Breeding for resistance to abiotic stresses in rice: the value of quantitative trait loci. In: Lamkey, K.R., Lee, M. (eds), Plant Breeding. Blackwell Publishing, pp. 201–212. Mackill, D.J., Amante

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Among the abiotic stress factors influencing the growth and productivity of wheat varieties, extremely high temperatures have the most limiting effect. In an experiment set up in the gradient chamber of the Martonvásár phytotron to test the effect of various temperatures on four winter wheat varieties and one variety of spelt, substantial differences were observed in the heat stress tolerance of the varieties. There was a considerable reduction in the number of shoots and spikes as the result of heat stress, leading to a drastic loss of grain yield. It was clear from changes in the biomass and in the grain:straw ratio that extremely high temperatures led to a substantial reduction in the ratio of grain to straw in the varieties tested. In response to high temperature the wheat plants turned yellow earlier due to the rapid decomposition of the chlorophyll content. This resulted in a considerable shortening of the vegetation period and early ripening. Reductions in the parameters tested were observed at different temperature levels for each variety, indicating considerable differences in the ability of the varieties to adapt to abiotic stress factors.

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Cereal Research Communications
Authors: A. Comeau, F. Langevin, V. Caetano, S. Haber, M. Savard, H. Voldeng, G. Fedak, Y. Dion, S. Rioux, J. Gilbert, D. Somers and R. Martin

It has proven to be an enduring and difficult challenge to generate useful germplasm that resists fusarium head blight (FHB) as effectively as Sumai 3. While focussed genetic approaches may follow a clear path to a well-defined goal of resistance, they run the risk of worsening traits not selected for. It was commonly believed that selecting for good performance under pressure from multiple diseases plus abiotic stress should be a harder task than focussing on the single goal of FHB resistance; and yet the complex, systemic approaches have now been shown to be capable of rapid progress. Moreover, the risks of worsening non-selected traits are lessened, because the selection matrices favour genes, or groups of genes, that are free of major defects arising from linkage or pleiotropy. However, even at the pre-breeding level, environments are needed that stress the tested germplasm abiotically and with multiple diseases, as a broad array of traits must be examined at the same time. Since as much as 98–99% of any population may need to be discarded, the widest possible genetic range of diversity should be investigated. As seen in several bread wheat examples, the critical factors that allow for rapid selection of germplasm resistant to most stresses are: a) use of an extensive range of available biodiversity; b) well-designed planning of numerous crosses; c) the astute application of combinations of biotic and abiotic stresses; and d) fast recycling of multiple-resistant lines into crossing blocks. Analyses of our first attempts (2003–07) with such systemic approaches show that as early as F1-F3, germplasm with minimal defects and resistant to the multiple biotic and abiotic stresses can be selected. This ability to identify and advance trait packages rather than just individual traits also improves efficiency for breeders. The selected germplasm resisted well all diseases of concern in Eastern Canada: FHB, barley yellow dwarf (BYD), rusts, powdery mildew, leaf spots, and root diseases. The best (e.g. FL62R1) had FHB resistance near equivalent to Sumai 3 while displaying good yield potential and agronomic traits. Milling quality still falls short of desired levels, but was a good improvement over Sumai 3. The systemic approach, so described because it integrates the pursuit of multiple traits in complex environments, has now demonstrated, in a Canadian setting, the success achieved earlier in Brazil. This confirmation and extension of the utility of systemic approaches support the case for their wider application.

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In order to target factors involved in plant-pathogen interactions, gene expression differences were investigated on pepper ( Capsicum annuum L.) plants after artificial infection with the bacterial pathogen Xanthomonas campestris pv. vesicatoria . Amplified Fragment Length Polymorphism investigations on reverse transcribed DNA fragments (cDNA-AFLP) were used to compare the expression profiles of parental lines and of resistant and susceptible individuals from pepper populations segregating for the gds gene, which confers a general defence system in pepper. In total, 73 transcript-derived fragments (TDFs) displaying differential expression patterns could be identified (presence-absence and/or different time courses in resistant and susceptible genotypes). Of these, 67 fragments were cloned and sequenced. In the case of several TDFs, sequence comparisons revealed close homologies to genes known to be responsible for abiotic stress or biotic elicitors, presenting potentially interesting targets for more detailed studies on gene expression and signal transduction.

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The biotic and abiotic stresses are the major limiting factors in plant productivity. To overcome these difficulties molecular breeding methods have recently been widely used to improve the stress and disease resistance of grapevine cultivars. Crown gall disease caused by Agrobacterium vitis or Agrobacterium tumefaciens causes serious damage worldwide on grapevine, and there is no efficient method yet that can be routinely used by grape-growers to prevent this disease. Therefore genetic manipulation for crown gall resistance would have a great economic impact. To this end embryogenic culture of Vitis berlandieri × Vitis rupestris cv. Richter 110 was transformed with a virE1 gene construct. Twenty-six plant lines were selected, and their transgenic nature was confirmed by PCR analysis. Seventeen of the 26 lines showed resistance to crown gall disease following inoculation with A. vitis Tm4 strain.

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Acta Botanica Hungarica
Authors: M. Kumar Singh, L. Balogh and K. Szabó

Sanita di Toppi, L. and Pawlik-Skowronska, B. (eds) (2003): Abiotic stresses in plants. - Kluwer Academic Publishers, Dordrecht, The Netherlands, 231 pp. (ISBN 1-4020-1648-4); Weber, E. (2003): Invasive plant species of the world: A reference guide to environmental weeds. - CAB International Publishing, Wallingford, 548 pp. (ISBN 0-85199-695-7); Werum, M. and Lange-Bertalot, H. (2004): Diatoms in springs from Central Europe and elsewhere under the influence of hydrogeology and anthropogenic impacts. pp. 9-417. Reichardt, E. (2004): Eine bemerkenswerte Diatomeenassoziation in einem Quellhabitat im Grazer Bergland, Österreich. pp. 419-480. - In: Lange-Bertalot, H. (ed.): Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 13. Ecology-Hydrogeology-Taxonomy. A. R. G. Gantner Verlag K. G. Ruggel, 480 pp.;

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Durum wheat landraces are still cultivated to take advantage of their excellent grain and straw quality, adaptation to abiotic stresses, and extremely wide variety of uses. The safeguarding and rehabilitation of genetic inheritance requires genetic characterization and evaluation. In this study, forty durum wheat landraces originating from Mediterranean countries were evaluated according to agro-morphological and technological properties. We show that the germplasm was highly variable. The mean yellow pigment and protein content was higher in landraces (15.58%; 7.32 ppm) than in the Moroccan cultivars used as controls (14.6%; 5.48 ppm). In addition, principal component analysis identified five groups showing variable agronomic and qualitative characteristics that might be useful in the rational design of breeding programs.

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