838 research outputs found
Pathogenic and molecular variability in a population of Mycosphaerella graminicola, cause of septoria tritici leaf blotch of wheat
Mycosphaerella graminicola, cause of Septoria tritici leaf blotch of wheat, is an important disease throughout the world. Information about the population structure of the pathogen is useful to improve control strategies. Molecular studies have shown that there was a high level of genetic variability within populations of M. graminicola, but no attempt was made to relate this variability to pathogenicity. The objectives of this research were to study a population of M. graminicola for both variability at the molecular level and pathogenicity and to determine whether any relationship between these two types of variability exists.
Ninety isolates of M. graminicola were collected using hierarchical sampling of leaves and lesions from 10 locations within a wheat field near Saskatoon. The isolates were tested for the degree of pathogenicity (aggressiveness) on a single susceptible cultivar and the components of pathogenicity, incubation period, latent period and disease severity, were evaluated. There were significant differences among isolates for all components at the lesion sampling level only but not at the leaf and location level. A subsample of 40 isolates was tested for variability for virulence on a set of six differential cultivars. A significant isolate x cultivar interaction was detected, but since the magnitude of the variability was low no attempt was made to classify the isolates into races.
Using 15 RAPD primers the percentage of polymorphic loci, number of molecular phenotypes (haplotypes) and gene diversity of 90 isolates were estimated. A high level of genetic variability was found within the population. Partitioning this variability into different components showed that most of the variability was distributed within locations. This type of distribution suggested that air-borne ascospores were the primary source of inoculum in the field. A similar type of distribution of genetic variability was detected using eight microsatellite markers.
Little relationship between molecular and pathogenic variability was found, suggesting that DNA fingerprinting has little value for monitoring the development of new virulent genotypes of the pathogen
The Story of the Torah from the Perspective of the Qur'an and History
The history of the Bible implies that the Torah has been formed and distorted over time. The Qur'an also confirms this issue. The Holy Qur'an, in addition to introducing the Jews as the People of the Book, uses the word "Torah" eighteen times, "which is a collection of divine teachings bestowed on Prophet Moses." On the one hand, the Holy Qur'an acknowledges and affirms it, and on the other hand, it attributes distortion to this book and introduces the Torah as one of the books that has been distorted throughout history, however, the holy Qurāan considers the part of the Torah that has been preserved to contain the teachings of God and can be acknowledged in general, and considers it a means of guiding the Jewish people and advises them to refer to it. The collection of information in this writing is library-based and their processing is descriptive-analytical. This article seeks to prove the view that the current Torah, with its various versions, has been disappeared in the ups and downs of the times, and that what exists is a very blurred and inconsistent face of the original version, and the Holy Qur'an confirms this
The Effect of Seed Priming on Germination and Seedling Growth of Watermelon (Citrullus Lanatus)
ABSTRACT Seed priming is a pre-sowing treatment which involves a controlled hydration of seeds, sufficient to allow pre-terminative metabolic events to take place while insufficient to allow radicle protrusion through the seed coat. This technique has been used to increase the germination rate, total germination and seedling uniformity, mainly under unfavorable environmental conditions. Little information is available about seedling development of watermelon to seed priming in field condition. To investigate the effect of seed priming on germination and seedling growth of watermelon, an experiment was conducted at Azad University of Sabzevar with factorial arrangement of treatment in a completely randomized design with 3 replications. Experimental factors were 3 watermelon cultivars (Niagara, Charleston Gray, and Crimson Sweet) and 5 priming media (HCL 0.1N, NaCl 1.5N, PEG 6000 3%, KNO 3 3%, and none primed). Priming increased watermelon emergence, emergence rate, and plumule length. No significant differences were found to exist on plumule dry weight and radicle length. Priming with PEG and NaCl negatively affected the rate and growth of emerged seedling. Among the assessed priming media, KNO 3 had the most effective impact on emergence and seedling growth. Compared with the non-primed seeds, seed priming with KNO3 increased the germination, germination rate and plumule length by 17.87%, 18.65%, and 4.68%, respectively
The Place of SiyÄq in the Interpretation of the Qur'an
The term SiyÄq (i.e. context) and its place and role in the interpretation of the Qur'an has always been considered by scholars and Qur'anic scholars. This term has been mentioned in the surviving narrative literature of the Infallibles (PBUT) as [connected word]. In fact, the principle of symmetry of the context and verbal and semantic order governing the body of the Qur'an, including verses and surahs, and even the arrangement of words and letters and their succession are among the principles inseparable from the word of God. It will help us to pay attention to this principle and applying it in the process of interpreting verses. In the current article, we try to get acquainted with the term context and its types, which are divided into contexts of words, sentences, verses and surahs, as well as its role and position in understanding Qurāanic verses, and the conditions for realizing the context and ways of proving and using it
An Effective Brain-Computer Interface System Based on the Optimal Timeframe Selection of Brain Signals
Background: Brain responds in a short timeframe (with certain delay) after the request for doing a motor imagery task and therefore it is most likely that the individual not focus continuously on the task at entire interval of data acquisition time or even think about other things in a very short time slice. In this paper, an effective brain-computer interface system is presented based on the optimal timeframe selection of brain signals.Methods: To prove the stated claim, various timeframes with different durations and delays selected based on a specific rule from EEG signals recorded during right/left hand motor imagery task and subsequently, feature extraction and classification are done.Results: Implementation results on the two well-known datasets termed Graz 2003 and Graz 2005; shows that the smallest systematically created timeframe of data acquisition interval have had the best results of classification. Using this smallest timeframe, the classification accuracy increased up to 91.43% for Graz 2003 and 88.96, 83.64 and 84.86 percent for O3, S4 and X11 subjects of Graz 2005 database respectively.Conclusion: Removing the additional information in which the individual does not focus on the motor imagery task and utilizing the most distinguishing timeframe of EEG signals that correctly interpret individual intentions improves the BCI system performance
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