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International audience; Diversity of agricultural systems can be described at different scales in terms of three main types of variables: technical management of cropping systems, farming systems and food supply chains. We focus on the diversity of technical management routes (TMRs), defined as logical successions of technical options (TOs) designed by the farmers. The study, comparison and assessment of this great diversity of complex routes are impossible with classical agronomic experiments or exhaustive assessments such as life cycle assessment (LCA). Hence, the selection of representative cases is necessary. Multidimensional data analysis methods permit the characterization of a diversity of TMRs and the construction of typologies but do not allow the consideration of the specific associations of TOs constituting the various TMRs. The aim of this paper is threefold: (i) to propose a new combined method, "Typ-iti", to classify the field TMRs of farmers, to identify key TO associations and to select the most relevant cases for study; (ii) to test this method on vineyard management diversity using a panel of vineyard fields of Loire Valley producers; and (iii) to discuss the capability of the proposed Typ-iti method for use in the characterization and selection of cases of other agricultural systems at diverse scales. The example developed in this paper is the selection of vineyard management cases for grape LCA combined with grape quality evaluation. The cases were selected to represent the regional diversity of management practices. A detailed on-farm survey of management methods was performed on a diverse range of wine production estates in the Middle Loire Valley. The Typ-iti method was constructed and implemented on the survey database. It combines a multidimensional analysis of qualitative survey data and typology and partitioning (clustering) associated with data mining methods (frequent pattern mining search and association rules). The surveyed sample was partitioned into 5 types of management practices, 2 of which were organic and 3 conventional. The partitioning was driven primarily by choices involving pest management and floor management. Each type was characterized by specific TOs, specific associations of TOs and remarkable TMRs. The cases were chosen on the basis of these 3 parameters. The Typ-iti method can be applied to other crops and at different scales; the only limitation is the availability of precise information on the practices used by farmers in their fields. (C) 2014 Elsevier B.V. All rights reserved.

The isotopically labelled S-3-(hexan-1-ol)-glutathione d 2 /d 3 (G3MHd 2 /d 3 ) was synthesized with a strategy based on acid-labile protecting groups. The natural analogue of this compound could be a precursor of 3-mercaptohexanol, a varietal thiol reminiscent of grape fruit, released during alcoholic fermentation. In a first time, deuterated glutathione conjugate was used to perform identification and quantification by stable isotope dilution assay of G3MH in musts from several varieties: Sauvignon, Riesling and Gewurztraminer. In a second time, synthetic and natural musts (Sauvignon Blanc) were spiked by G3MHd 2 /d 3 at different levels from 12 to 150 μg L −1 to demonstrate the relationship between 3-mercaptohexan-1-ol (3MH) and G3MH. GC–ITMS/MS analysis of the resulting wines clearly showed the formation of the corresponding deuterated 3MH, that proves the direct connection with G3MH under enological conditions. In Sauvignon Blanc grape juice, a conversion yield of 4.4% was found in duplicate for an initial spiking of G3MH d 2 /d 3 equivalent to 12 μg L −1 .