Mohammad Jawhar

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The fungus Cochliobolus sativus is the causal agent of barley common root rot disease. Twenty-two isolates of diverse geographical origin within Syria were studied in relation to pathogenicity, analysis of genomic DNA through random amplified polymorphic DNA (RAPD) and variation within the nuclear rDNA [internal transcribed spacers (ITS)]. The data(More)
Spot blotch caused by Cochliobolus sativus has been the major yield-reducing factor for barley production during the last decade. In this study, a systematic sequencing of expressed sequence tags (EST) was chosen to obtain a global picture of the assembly of genes involved in pathogenesis. To identify a large number of plant EST, which are induced at(More)
Spot blotch, caused by Cochliobolus sativus, is a common foliar disease of barley that is controlled primarily through the development of resistant cultivars. An assay involving the inoculation of a detached first leaf (DFL) maintained in vitro was used to determine the reaction of five barley genotypes to the disease. The estimation of the infected leaf(More)
The effects of 0,5 and 10 Gy doses of gamma irradiation on the enhancement of embryogenesis and plant regeneration efficiency of three barley (Hordeum vulgare L.) genotypes, Igri, Arabi Abiad and AECS 76, were evaluated. Embryo yields at 5 and 10 Gy doses were significantly higher than those of the control (OGy). This effect was genotype-dependent. The most(More)
IGS-RFLP markers were used to determine the genetic structure of Syrian field populations of the barley leaf stripe pathogen Pyrenophora graminea. Genetic variation was high in Syrian populations of P. graminea. A total of 366 scorable DNA bands were obtained, and 290 of these (79.2%) were polymorphic. Genetic distances among all isolates ranged from 0.01(More)
Systemic movement of Pyrenophora graminea in five barley genotypes was used to quantify the infection level of leaf stripe disease. The systemic movement of the fungus was slower in the resistant than in the susceptible genotypes and enabled easy differentiation among them. Significant correlations were found (P = 0.001) between relative in vitro value and(More)
Xylanase and amylase have gained increasing interest because of their various biotechnology applications. In this research, the restriction of PCR-amplified internal transcribed spacers (ITS) of ribosomal DNA (rDNA) was used to confirm the genetic variation among 22 isolates of Pyrenophora graminea differing in their xylanase and amylase production. The(More)
Field research was undertaken to investigate the effects of potassium K2SO4 (36% K) as a foliar spray and/or soil application on grain yield, 1000-grain weight and severity of Septoria tritici blotch on wheat during 1998 and 1999. Two Syrian bread wheat cultivais (Bohuth 6 and Cham 6) and one promising mutant line (L92-6) were used in this study. Six(More)
Spot blotch caused by the hemibiotrophic pathogen Cochliobolus sativus has been the major yield-reducing factor for barley production during the last decade. Monitoring transcriptional reorganization triggered in response to this fungus is an essential first step for the functional analysis of genes involved in the process. To characterize the defense(More)
Pyrenophora graminea, the causal agent of leaf stripe of barley, is an economically important disease with a worldwide distribution. To examine the inheritance of virulence in this fungus, a cross was made between two isolates that differed widely in their DNA and virulence. Of the 70 progeny tested, 36 exhibited high virulence and 34 exhibited low(More)