-Sunflower (Helianthus annuus L.) crop is often labelled as environmental-friendly for many objective reasons: limited amounts of N fertiliser, no irrigation, and limited use of pesticides. In addition, sunflower has a potential for providing multiple ecosystem services in diverse cropping systems (e.g. pollinators feeding). However agroecological innovations have been less developed or disseminated than for cereals or oilseed rape. Based on results from the sunflower research consortium in Toulouse (Mestries and Debaeke. 2016. Journées d'échanges Tournesol, 28 et 29 juin 2016, Toulouse (France)), we illustrate some innovating and promising approaches for more agroecological practices in sunflower cropping. Our results suggested that: integrated crop management could be proposed to limit the use of pesticides and mitigate crop damages; cover crops could be used as biofumigants to control soilborne diseases in sunflower; intercropping sunflower with soybean could be a valuable option for maximizing resource-use efficiency in low-input environments; sunflower yield could be maintained at good level in very low input cropping systems. Previous examples point out how agroecological principles could be applied to sunflower crop to improve its production in low-input conditions, and enhance the ecosystem services deliverable by this oilseed crop.Keywords: cultural control / intercropping / ecosystem services / cropping systems / low-input Résumé -La culture de tournesol : respectueuse de l'environnement et agroécologique. La culture de tournesol (Helianthus annuus L.) est souvent qualifiée de respectueuse de l'environnement en raison de sa faible dépendance aux apports d'engrais, à l'eau d'irrigation et aux applications de pesticides en végétation. Par ailleurs, le tournesol contribue à de nombreux services écosystémiques au premier rang desquels l'alimentation des pollinisateurs. Cependant, très peu d'innovations agroécologiques ont été mises en avant sur cette culture contrairement à ce qui a été développé en céréales ou en colza. En nous basant sur les travaux récents du consortium de recherche sur le tournesol basé à Toulouse (Mestries et Debaeke. 2016. Journées d'échanges Tournesol, 28 et 29 juin 2016, Toulouse (France)), nous illustrerons plusieurs approches innovantes et prometteuses pour augmenter la performance agroécologique de la culture de tournesol. Ainsi nos résultats montrent que : des méthodes de protection intégrée peuvent être proposées pour limiter l'application de pesticides et atténuer les pertes de rendement ; des cultures intermédiaires (brassicacées) pourraient être utilisées pour la biofumigation des sols et le contrôle de maladies telluriques en tournesol ; l'association culturale avec le soja pourrait constituer une option intéressante pour maximiser l'utilisation des ressources en bas intrants ; le rendement du tournesol peut être maintenu à un bon niveau dans des systèmes à très bas niveaux d'intrants. Les exemples précédents illustrent comment les principes de l'agroécologie peuv...

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Three inoculation methods were evaluated for effectiveness to cause sunflower premature ripening (PR). Evaluations were conducted on a sunflower (Helianthus annuus) cultivar susceptible to PR in replicated, multilocation experiments under greenhouse conditions. Plants were inoculated with Phoma macdonaldii, either with mycelium, conidia, or infected residues at the stem base or with buried residues. Disease severity (DS) was measured by percent girdling necrosis at the stem base and percent final PR; the infection spread was assessed using the area under the disease progress curve (AUDPC). Inoculation with mycelia or 1 × 106 spores/ml caused significantly more DS and PR than lower spore concentrations or infected residues (P < 0.05). Amending soil with residues induced root necrosis but no PR. P. macdonaldii was mainly isolated at the stem base and above but rarely on root systems. Microscopic evaluations showed that hyphae colonized mainly the cortex and vascular stem tissues. The overall results demonstrated a clear role of aerial infection in PR compared with soilborne inoculum, and that inoculation at the stem base with a spore suspension could be used for screening genotypes for resistance to PR.

The aim of this study was to characterise the sequence of traits that influence the response of rice morphogenesis to a shortage in carbohydrate supply and to its recovery. Plants were grown under 70% shading or full-light exposure for distinct periods during the vegetative and early reproductive phases in field and controlled environments. Lower organ vigour (i.e. higher specific leaf area and specific stem length), sugar concentration, tiller emergence and leaf elongation rate; higher leaf blade to sheath length ratio and preferential assimilate allocation to sink (elongating) leaves, were observed soon after the onset of shading. Organ vigour was affected before any appreciable effect on tiller emergence was noted. All the processes resumed after the shading removal, which coincided with a boost in sugar concentration; however, the extent of recovery in organ vigour and tillering depended on the growth stage at which shading was applied. It is concluded that crop response to changes in carbohydrate supply at the early stage favoured leaf area production by adjusting transient reserve levels and biomass allocation. Results of this study provide further insights into the role of soluble carbohydrates in plant and crop phenotypic plasticity and, thus, into the value of such processes in plant growth models. (Résumé d'auteur

In order to make more efficient plant breeding and gain in competitiveness, the sector of oil-protein crops decided to intensify agronomic research on sunflower crop. The “Sunflower” Joint Technological Unit (Unité Mixte Technologique (UMT) “Tournesol”, in French) was launched in the Toulouse area in 2006, associating closely INRA and Terres Inovia. First focused on improving oil production through an agronomic approach, the UMT was renewed in 2011 with a broader partnership and a more assertive orientation towards the development of decision-making tools. The objective of this paper is to highlight the relevance and productivity of this user-oriented research facility. The main results relate to (i) the co-construction of a simulation model (SUNFLO) that can be parameterized and manipulated by Terres Inovia engineers, (ii) the joint exploration of supra-field scales and new methods for agronomic diagnosis and yield forecasting based on remote sensing, (iii) the tuning and dissemination of operational decision rules, (iv) the production of essential knowledge on emergent and/or damaging fungal diseases, as well as on complex interactions between genotype, environment and crop management. After a concluding symposium in 2016, new requests for sunflower research were formulated by the participants. They also advocated for a diversification of crops to consider in order to better meet the needs of the whole oil-protein sector.