Improved control of Septoria tritici blotch in durum wheat using cultivar mixtures

Mixtures of cultivars with contrasting levels of disease resistance are capable of suppressing infectious diseases in wheat, as demonstrated in numerous field experiments. Most studies focused on airborne pathogens in bread wheat, while splash-dispersed pathogens have received less attention, and no studies have been conducted in durum wheat. We conducted a two-year field experiment in Tunisia, a major durum wheat producer in the Mediterranean region, to evaluate the performance of cultivar mixtures in controlling the polycyclic, splash-dispersed disease Septoria tritici blotch (STB) in durum wheat. To measure STB severity, we used a novel, high-throughput method based on digital analysis of images captured from 3074 infected leaves collected from 42 and 40 experimental plots on the first and the second year, respectively. This method allowed us to quantify pathogen reproduction on wheat leaves and to acquire a large dataset that exceeds previous studies with respect to accuracy and statistical power. Our analyses show that introducing only 25% of a disease-resistant cultivar into a pure stand of a susceptible cultivar provides a substantial reduction of almost 50% in disease severity. However, adding a second resistant cultivar to the mixture did not further improve disease control, contrary to predictions of epidemiological theory. Susceptible cultivars can be agronomically superior to resistant cultivars or be better accepted by growers for other reasons. Hence, if mixtures with only a moderate proportion of the resistant cultivar provide similar degree of disease control as resistant pure stands, as our analysis indicates, such mixtures are more likely to be accepted by growers

Towards a TTCN-3 Test System for Runtime Testing of Adaptable and Distributed Systems

Part 3: Test Frameworks for Distributed SystemsInternational audienceToday, adaptable and distributed component based systems need to be checked and validated in order to ensure their correctness and trustworthiness when dynamic changes occur. Traditional testing techniques can not be used since they are applied during the development phase. Therefore, runtime testing is emerging as a novel solution for the validation of highly dynamic systems at runtime. In this paper, we illustrate how a platform independent test system based on the TTCN-3 standard can be used to execute runtime tests. The proposed test system is called TT4RT: TTCN-3 test system for Runtime Testing. A case study in the telemedicine field is used as an illustration to show the relevance of the proposed test system

International Conference on Acoustics and Vibration

The book provides readers with a snapshot of recent research and industrial trends in field of industrial acoustics and vibration. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at International Conference on Acoustics and Vibration (ICAV2016), which was organized by the Tunisian Association of Industrial Acoustics and Vibration (ATAVI) and held March 21-23, in Hammamet, Tunisia. The contributions, mainly written by north African authors, covers advances in both theory and practice in a variety of subfields, such as: smart materials and structures; fluid-structure interaction; structural acoustics as well as computational vibro-acoustics and numerical methods. Further topics include: engines control, noise identification, robust design, flow-induced vibration and many others.This book provides a valuable resource for both academics and professionals dealing with diverse issues in applied mechanics. By combining advanced theories with industrial issues, it is expected to facilitate communication and collaboration between different groups of researchers and technology users

Durum Wheat Mediterranean Landraces: A Valuable Source for Resistance to Tan Spot Disease

Tan spot (TS), caused by Pyrenophora tritici-repentis (Ptr), has gained significant importance in Tunisia. In this study, a Mediterranean durum wheat collection of 113 accessions were evaluated under field conditions, during the 2018–2019 cropping season, for resistance to Ptr at Koudia experimental station in Bou Salem (Tunisia). The disease progress curve (AUDPC) was used to screen this collection, and the effect of days to heading (DH) and plant height (PH) were evaluated in relation to TS resistance. No significant correlation of PH with AUDPC was found, yet a significant correlation (r = 0.212, p ≤ 0.05) was established between DH and AUDPC scores, suggesting that DH may have an effect on TS development. Moreover, correlation between seedling and adult reactions was significant (r = 0.695, p ≤ 0.001). Although susceptible accessions clustered separately from resistant accessions, the clustering was independent of the country of origin and the status of improvement of the wheat accessions. In total, 67% and 80% of resistant and moderately resistant accessions, respectively, were landraces, suggesting therefore the possible presence of novel sources of resistance to Ptr in some landraces, which can be used to establish a breeding program for resistance to tan spot disease

Prediction of the dynamic behavior of a structure treated by particle damper

International audiencePrediction of the dynamic behavior of a structure treated by particle dampe