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Tomaten zählen zu den weltweit am meisten verbreiteten Kulturen und sind als wichtige Kulturpflanzeim Freiland und imgeschützten Anbau vertreten. Sowohl Wassermangel als auch eindamit häufig einhergehender Nährstoffmangelstress stellen Tomatenproduzenten insbesondereim Freiland vor große Probleme. LösungenfüreineressourcenschonendeProduktion,auchunterdemAspektklimabedingterVerknappung,sindnotwendig,umErnteerträge zu erhalten undgleichzeitig die Umwelt zu schützen. Rund 200 Wissenschaftler und Techniker aus zehn europäischenLändern sind im Rahmen des TOMRES-Projektes an der Forschung beteiligt, die zu „sparsameren“Tomatensorten führen soll.

The report collates the practice abstracts developed by TOMRES upto M42 and disseminated through internal and external platforms (EIP-Agri) during the project implementation.

At the end of the annual horticultural production cycle of greenhouse-grown crops, large quantities of residual biomass are discarded. Here, we propose a new value chain to utilize horticultural leaf biomass for the extraction of secondary metabolites. To increase the secondary metabolite content of leaves, greenhouse-grown crop plants were exposed to low-cost abiotic stress treatments after the last fruit harvest. As proof of concept, we evaluated the production of the flavonoid rutin in tomato plants subjected to nitrogen deficiency. In an interdisciplinary approach, we observed the steady accumulation of rutin in young plants under nitrogen deficiency, tested the applicability of nitrogen deficiency in a commercial-like greenhouse, developed a high efficiency extraction for rutin, and evaluated the acceptance of the proposed value chain by its key actors economically. On the basis of the positive interdisciplinary evaluation, we identified opportunities and challenges for the successful establishment of horticultural leaf biomass as a novel source for secondary metabolites.

The fungal pathogen Cercospora beticola causes the most destructive foliar diseas eof sugar beet, namely Cercospora leaf spot (CLS), which results in economically important yield losses. Current breeding efforts aim at developing sugar beet lines with lower fungal susceptibility as well as high productivity to ensure reduced fungicide applications in the context of integrated pest management. However, the main challenge remains to select sugar beet genotypes that produce the required yield quality and quantity, and to quantify their defense ability. Well-established visual disease scoring can be supported and supplemented by new techniques that enable earlier disease detection and genotype resistance classification. In this thesis, visual disease scoring was combined with novel invasive and non-invasive techniques toanalyze shoot and root disease responses to Cercospora infection. The fungal growth within the sugar beet leaf tissue was quantified using molecular analysis of the fungal calmodulin gene. This allows for the pre-selection of resistant genotypes before disease symptoms were visible. It could be shown that plants with high susceptibility (HS) allowed a stronger fungal colonization in the leaf tissue than ones with low susceptibility (LS). These results correlated with the respective disease severity. The HS genotypes consistently displayed more severe disease symptoms than LS plants. In particular, the moderately susceptible (MS) genotype seemed to be a promising candidate according to its variable response indicating a more adaptable reaction to changing environmental conditions. Therefore, this MS genotype might produce more yield under low-to-moderate disease pressure compared with HS plants, which would be comparatively more strongly infected and deliver reduced yield. The cuticle forms a barrier between the plant and the environment and therefore provides resistance against pathogens. Cuticular wax may affect host-pathogen recognition and conidia adhesion on the leaf surface. In this study, LS plants werefound to contain larger amounts of cuticular waxes. Mature leaves, which showed reduced fungal colonization, also had higher wax levels than immature leaves. Further experiments are needed to investigate the precise role of sugar beet cuticular waxes on C. beticola infections.[...]

Background Combined assessment of leaf reflectance and transmittance is currently limited to spot (point) measurements. This study introduces a tailor-made hyperspectral absorption-reflectance-transmittance imaging (HyperART) system, yielding a non-invasive determination of both reflectance and transmittance of the whole leaf. We addressed its applicability for analysing plant traits, i.e. assessing Cercospora beticola disease severity or leaf chlorophyll content. To test the accuracy of the obtained data, these were compared with reflectance and transmittance measurements of selected leaves acquired by the point spectroradiometer ASD FieldSpec, equipped with the FluoWat device. Results The working principle of the HyperART system relies on the upward redirection of transmitted and reflected light (range of 400 to 2500 nm) of a plant sample towards two line scanners. By using both the reflectance and transmittance image, an image of leaf absorption can be calculated. The comparison with the dynamically high-resolution ASD FieldSpec data showed good correlation, underlying the accuracy of the HyperART system. Our experiments showed that variation in both leaf chlorophyll content of four different crop species, due to different fertilization regimes during growth, and fungal symptoms on sugar beet leaves could be accurately estimated and monitored. The use of leaf reflectance and transmittance, as well as their sum (by which the non-absorbed radiation is calculated) obtained by the HyperART system gave considerably improved results in classification of Cercospora leaf spot disease and determination of chlorophyll content. Conclusions The HyperART system offers the possibility for non-invasive and accurate mapping of leaf transmittance and absorption, significantly expanding the applicability of reflectance, based on mapping spectroscopy, in plant sciences. Therefore, the HyperART system may be readily employed for non-invasive determination of the spatio-temporal dynamics of various plant properties. Electronic supplementary material The online version of this article (doi:10.1186/s13007-015-0043-0) contains supplementary material, which is available to authorized users.