Stay-green wheat for Australia's changing; dry environment

Tese de doutoramento em Ciências e Tecnologias da Informação, apresentada ao Departamento de Engenharia Informática da Faculdade de Ciências e Tecnologia da Universidade de CoimbraThis doctoral thesis investigates user provided networks. Such networks have become important research subjects in the field of informatics engineering due to the recent popularity of smart phones. User provided networks are independent from traditional Internet service providers. Communication and information exchange between users occurs opportunistically, i.e., when the smart phones are close enough to exchange information. Most user provided networks are based on the radio standard IEEE 802.11, popularly known as 'wi-fi'. However, some networks are based on other low range radio standards, such as Bluetooth and IEEE 802.15.4. User provided networks are important to the society in general when the traditional Internet service providers become unavailable. For example, this may occur in terrorist attacks, earthquakes, or even cyber attacks. In these emergency situations, when users have a greater interest in common, an efficient system for non-presencial information exchange is necessary. Such networks are also interesting in a social context, when users must be incentivized to share their resources (storage capacity, wireless connectivity and battery) to enable the exchange of information. This doctoral thesis addresses both situations: i) networks whose users have a common interest and ii) networks whose users need to be encouraged to share resources. Among the various contributions of this doctoral thesis are the Delay Tolerant Reinforcement-Based routing solution and the Messages on oFfer incentive mechanism. The first is a routing solution for users-provided networks when the users have a prior interest in common. The second is an incentive mechanism to encourage users to exchange information. Both solutions showed excellent results in the simulation environment.Esta tese de doutoramento investiga as redes providas pelos usuários. Com a popularização do telemóvel esperto (smart phone) tais redes se tornaram objeto de pesquisa na área de engenharia informática. Uma característica básica das redes providas pelo usuário é a sua independência em relação aos provedores de serviço tradicionais. A comunicação e troca de informação entre usuários ocorre de forma oportuna, isto é, quando os telemóveis estão próximos o suficiente para se comunicarem. A maioria das redes providas por usuários é baseada no padrão de rádio IEEE 802.11, popularmente conhecido como 'wi-fi'. No entanto, algumas redes se baseiam em outros padrões de baixo alcance, por exemplo Bluetooth e IEEE 802.15.4. As redes providas por usuários são importantes para a sociedade no advento dos provedores de serviço tradicionais ficarem indisponíveis. Por exemplo, isso pode ocorrer em ataques terroristas, terremotos, ou mesmo em ataques virtuais. Nessas situações de emergência, quando os usuários têm um interesse maior em comum, é necessário um sistema de troca de mensagens não presencial eficiente. Tais redes também são importantes em um contexto social, quando os usuários precisam ser incentivados a compartilhar os seus recursos (capacidade de armazenamento, conectividade sem-fio e bateria) para que ocorra troca de informação. Essa tese de doutoramento aborda ambas as situações: i) redes cujos usuários têm um interesse em comum e ii) redes cujos usuários precisam ser incentivados a compartilhar recursos. Dentro das diversas contribuições que esta tese de doutoramento apresenta estão a solução de roteamento Delay Tolerant Reinforcement-Based e o mecanismo de incentivo Messages on oFfer. A primeira é uma solução de encaminhamento para redes providas por usuários que tenham um interesse em comum prévio. A segunda é um mecanismo de incentivo para estimular que os usuários troquem informação quando não houver o interesse em comum. Ambas as soluções apresentaram excelentes resultados no ambiente de simulação desenvolvido nesta tese.FCT - PTDC/EEA-TEL/103637/200

An automated, cost-effective and scalable, flood-and-drain based root phenotyping system for cereals

Background: Genetic studies on the molecular mechanisms of the regulation of root growth require the characterisation of a specific root phenotype to be linked with a certain genotype. Such studies using classical labour-intensive methods are severely hindered due to the technical limitations that are associated with the impeded observation of the root system of a plant during its growth. The aim of the research presented here was to develop a reliable, cost-effective method for the analysis of a plant root phenotype that would enable the precise characterisation of the root system architecture of cereals. Results: The presented method describes a complete system for automatic supplementation and continuous sensing of culture solution supplied to plants that are grown in transparent tubes containing a solid substrate. The presented system comprises the comprehensive pipeline consisting of a modular-based and remotely-controlled plant growth system and customized imaging setup for root and shoot phenotyping. The system enables an easy extension of the experimental capacity in order to form a combined platform that is comprised of parallel modules, each holding up to 48 plants. The conducted experiments focused on the selection of the most suitable conditions for phenotyping studies in barley: an optimal size of the glass beads, diameters of the acrylic tubes, composition of a medium, and a rate of the medium flow. Conclusions: The developed system enables an efficient, accurate and highly repeatable analysis of the morphological features of the root system of cereals. Because a simple and fully-automated control system is used, the experimental conditions can easily be normalised for different species of cereals. The scalability of the module-based system allows its capacity to be adjusted in order to meet the requirements of a particular experiment

Genotypic variation in the ability of wheat roots to penetrate wax layers

The role of the root system in mediating crop yields has recently been emphasised, resulting in several laboratory approaches for phenotyping root traits. We aimed to determine the existence of, and reasons for, genotypic variation in wheat (Triticum aestivum L.) root penetration of strong wax layers. Three contrasting groups (UK elite lines, CIMMYT lines and near-isogenic lines of cv Mercia containing dwarfing and semi-dwarfing Rht alleles) comprising 18 different genotypes with contrasting phenologies were studied. We determined the ability of roots of these genotypes to penetrate strong wax layers and the angular spread of the root systems. There were no intrinsic differences in root system ability to penetrate strong wax layers (consistent with the similar root diameter of all lines) since greater root penetration was simply related to more root axes. Recording root penetration of concentric zones of the wax layer demonstrated that cv. Battalion had a root system with a smaller angular spread than cv. Robigus, which had the root system with the greatest angular spread. There was limited genotypic variability in root penetration of strong layers within the wheat cultivars studied. A key challenge will be to determine the physiological and agronomic significance of the variation in root angular spread