Combining a multi-environment trial and a diagnosis method to assess potential yield and main limiting factors of three highly different pea types

International audienceThe evaluation of varieties of cultivated species is based on the implementation of multi-environmental trials thatshow high performances or strong limitations in some environments. To know the cause of these limitations, andto reason the adaptation of varieties to different environments, we propose a combined approach between theclassical analysis of experimental results and a diagnostic approach using the DiagVar tool, which allows toassess the impact of limiting factors in each trial, the potential yield and the sensitivity of cultivars to thosefactors. This procedure is applied in a large and diversified field trial network including eight locations and threeyears to the comparison of two to four cultivars of the three agronomical pea types: spring peas, hr-winter peas(non-reactive to photoperiod) and Hr-winter peas (reactive to photoperiod).Estimates of potential yields from DiagVar for the three pea types were consistent with the experimental results, with higher values for hr-winter cultivars than for spring and Hr-winter ones. We shed light on specificlimiting factors for each type, some of them being rarely quantified previously, which allows us to better targetspecific regions or environments for each pea type. Thus, spring types were more impacted by early limitingfactors (loss of plants, low temperatures and radiation, lack of water, leading to reduced growth) and end-ofcycle stresses (high temperatures, water stress). Diseases had higher impacts on both winter types. Here weshow for the first time that the lack of solar radiation affected particularly hr-winter type and the low cropnitrogen status affected more frequently spring peas. These results highlight the interest of carrying out anagronomic diagnosis in the analysis of varietal multi-environment trials, revealing the most important limitingfactors to take into account while breeding new pea cultivars, particularly limiting factors that are difficult todirectly observe. This method proves to be reliable and informative for breeders, technicians and agriculturaladvisors to discuss the adaptation of varieties to specific environment

Marine ecosystems’ responses to climatic and anthropogenic forcings in the Mediterranean

International audienceThe semi-enclosed nature of the Mediterranean Sea, together with its smaller inertia due to the relative short residence time of its water masses, make it highly reactive to external forcings, in particular variations of water, energy and matter fluxes at the interfaces. This region, which has been identified as a “hotspot” for climate change, is therefore expected to experience environmental impacts that are considerably greater than those in many other places around the world. These natural pressures interact with the increasing demographic and economic developments occurring heterogeneously in the coastal zone, making the Mediterranean even more sensitive. This review paper aims to provide a review of the state of current functioning and responses of Mediterranean marine biogeochemical cycles and ecosystems with respect to key natural and anthropogenic drivers and to consider the ecosystems’ responses to likely changes in physical, chemical and socio-economical forcings induced by global change and by growing anthropogenic pressure at the regional scale. The current knowledge on and expected changes due to single forcing (hydrodynamics, solar radiation, temperature and acidification, chemical contaminants) and combined forcing (nutrient sources and stoichiometry, extreme events) affecting the biogeochemical fluxes and ecosystem functioning are explored. Expected changes in biodiversity resulting from the combined action of the different forcings are proposed. Finally, modeling capabilities and necessity for modeling are presented. A synthesis of our current knowledge of expected changes is proposed, highlighting relevant questions for the future of the Mediterranean ecosystems that are current research priorities for the scientific community. Finally, we discuss how these priorities can be approached by national and international multi-disciplinary research, which should be implemented on several levels, including observational studies and modeling at different temporal and spatial scales