Analyse de la mise en œuvre de règles de décision de systèmes en production intégrée en Lorraine

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du colloque national DEPHY, qui s’est déroulé les 13 et 14 novembre 2018 à la Cité des Sciences et de l'Industrie (Paris). Nous vous invitons à découvrir le bilan et les enseignements des 21 projets conduits sur la période 2012-2017.As part of DEPHY EXPE network from Ecophyto programme, four test platforms were implanted in2011/2012 on Lorrain territory to test integrated production. This project aims to cut in half pesticidesuse but it was also an opportunity to knock down the technical barriers related to constraints as regardssoil, climate and regulation which impact farming systems of the region. Two levels of change(lengthening the rotation or not) were tested in the platforms. Sometimes, decision rules on systemsmanagement techniques, preliminary defined to meet specific objectives, needed to be adapted over time depending on their success or their failure. Experimenting these cropping systems providedlearnings on beneficial or adverse effects of lengthening the rotation, and on alternative means usedagainst pests. For instance, adjust treatment threasholds and use species associations could preventfungicide and insecticide treatments, but mechanical weeding wasn't sufficient on rape and had to becombined with herbicides used in reduced quantities. These platforms were not only a source oftechnical references but also appropriate teaching supports.Dans le cadre du réseau DEPHY EXPE du programme Ecophyto, quatre plateformes expérimentalesont été implantées en 2011/2012 sur le territoire lorrain pour tester la production intégrée. Ce projet,visant une réduction de 50% des produits phytosanitaires, fut aussi une opportunité pour lever lesverrous techniques liés aux contraintes pédologiques, climatiques et réglementaires qui mettent à malles systèmes agricoles lorrains actuels. Deux niveaux de rupture (avec ou sans allongement de larotation) ont été testés sur les plateformes. Les règles de décision sur les itinéraires techniques dessystèmes, définies en amont pour répondre à des objectifs précis, ont parfois dû être adaptées au coursdu temps selon leur réussite ou leur échec.La conduite de ces essais systèmes a ainsi permis de tirer des enseignements sur l'intérêt del'allongement de la rotation et sur les différents leviers alternatifs aux produits phytosanitaires utilisés.Par exemple, des traitements fongicides et insecticides ont pu être évités en adaptant les seuilsd'intervention ou avec des associations d'espèces, mais il a été nécessaire de coupler le désherbagemécanique sur colza à un désherbage chimique en dose réduite. Ces plateformes ont pu être la sourcede références techniques mais aussi des supports pédagogiques très pertinents

Analyse de la mise en œuvre de règles de décision de systèmes en production intégrée en Lorraine

Dans le cadre du réseau DEPHY EXPE du programme Ecophyto, quatre plateformes expérimentales ont été implantées en 2011/2012 sur le territoire lorrain pour tester la production intégrée. Ce projet, visant une réduction de 50% des produits phytosanitaires, fut aussi une opportunité pour lever les verrous techniques liés aux contraintes pédologiques, climatiques et réglementaires qui mettent à mal les systèmes agricoles lorrains actuels. Deux niveaux de rupture (avec ou sans allongement de la rotation) ont été testés sur les plateformes. Les règles de décision sur les itinéraires techniques des systèmes, définies en amont pour répondre à des objectifs précis, ont parfois dû être adaptées au cours du temps selon leur réussite ou leur échec. La conduite de ces essais systèmes a ainsi permis de tirer des enseignements sur l'intérêt de l'allongement de la rotation et sur les différents leviers alternatifs aux produits phytosanitaires utilisés. Par exemple, des traitements fongicides et insecticides ont pu être évités en adaptant les seuils d'intervention ou avec des associations d'espèces, mais il a été nécessaire de coupler le désherbage mécanique sur colza à un désherbage chimique en dose réduite. Ces plateformes ont pu être la source de références techniques mais aussi des supports pédagogiques très pertinents.As part of DEPHY EXPE network from Ecophyto programme, four test platforms were implanted in 2011/2012 on Lorrain territory to test integrated production. This project aims to cut in half pesticides use but it was also an opportunity to knock down the technical barriers related to constraints as regards soil, climate and regulation which impact farming systems of the region. Two levels of change (lengthening the rotation or not) were tested in the platforms. Sometimes, decision rules on systems management techniques, preliminary defined to meet specific objectives, needed to be adapted over [br/] time depending on their success or their failure. Experimenting these cropping systems provided learnings on beneficial or adverse effects of lengthening the rotation, and on alternative means used against pests. For instance, adjust treatment threasholds and use species associations could prevent fungicide and insecticide treatments, but mechanical weeding wasn't sufficient on rape and had to be combined with herbicides used in reduced quantities. These platforms were not only a source of technical references but also appropriate teaching supports

Barley soil borne mosaic viruses: Identification of predominant viruses affecting yield and malting quality, in order to orientate breeding towards a sustainable resistance

Genetic resistance is the only way to control mosaic damage in winter barley. At least 18 resistance genes are known, but until recently, rym4 was the most used by breeders to control Barley yellow mosaic virus-1 (BaYMV-1), predominant in France and Barley mild mosaic virus (BaMMV). However, since 2009, new significant damage has been observed in malting barley in a widening production area, indicating possible overcoming of resistance, with the development of BaYMV-2. The objectives of the Mosa-hordeum project were to: identify new viruses or pathotypes; develop new detection tools; confirm cultivar resistance observed in field using MB tools; confirm efficiency of resistance genes cited in literary reviews; quantify impact on yield and malting quality. A complete viral inventory was carried out 2013- 2016 on affected barley crops in 108 sites using: real-time PCR; Sanger sequencing; Next-Generation Sequencing; and serological tests. A new tool, based on derived Cleaved Amplified Polymorphic Sequences (dCAPS), developed to investigate BaYMV-1 and 2 distributions, demonstrated that BaYMV-2 is predominant (> 95%) in diseased samples. BaYMV-1 and BaMMV were also identified in co-infection with BaYMV-2 on susceptible cultivars. Comparison of yield components, malting and beer quality obtained on healthy/contaminated plots with couples of cultivars revealed variation in yield losses, up to 3t/ha, reduction in number of spikes and kernels/m², smaller kernels, slight increase in protein content and decrease of malt extract. Phylogenetic analyses indicated that the rym4 resistance-breaking ability of BaYMV-2 independently evolved on multiple occasions. In limited number of trials, rym5 resistance was overcome by a variant of BaMMV. The implantation of differentials in 21 contaminated trials confirmed the efficiency of 11 resistance genes against the BaYMV-2/BaMMV complex. To monitor BaYMV and BaMMV resistance for registration in the National List real-time PCR appears more efficient than dCAPS. These findings will help breeders achieve sustainable resistance

Barley soil borne mosaic viruses: Identification of predominant viruses affecting yield and malting quality, in order to orientate breeding towards a sustainable resistance

Genetic resistance is the only way to control mosaic damage in winter barley. At least 18 resistance genes are known, but until recently, rym4 was the most used by breeders to control Barley yellow mosaic virus-1 (BaYMV-1), predominant in France and Barley mild mosaic virus (BaMMV). However, since 2009, new significant damage has been observed in malting barley in a widening production area, indicating possible overcoming of resistance, with the development of BaYMV-2. The objectives of the Mosa-hordeum project were to: identify new viruses or pathotypes; develop new detection tools; confirm cultivar resistance observed in field using MB tools; confirm efficiency of resistance genes cited in literary reviews; quantify impact on yield and malting quality. A complete viral inventory was carried out 2013- 2016 on affected barley crops in 108 sites using: real-time PCR; Sanger sequencing; Next-Generation Sequencing; and serological tests. A new tool, based on derived Cleaved Amplified Polymorphic Sequences (dCAPS), developed to investigate BaYMV-1 and 2 distributions, demonstrated that BaYMV-2 is predominant (> 95%) in diseased samples. BaYMV-1 and BaMMV were also identified in co-infection with BaYMV-2 on susceptible cultivars. Comparison of yield components, malting and beer quality obtained on healthy/contaminated plots with couples of cultivars revealed variation in yield losses, up to 3t/ha, reduction in number of spikes and kernels/m², smaller kernels, slight increase in protein content and decrease of malt extract. Phylogenetic analyses indicated that the rym4 resistance-breaking ability of BaYMV-2 independently evolved on multiple occasions. In limited number of trials, rym5 resistance was overcome by a variant of BaMMV. The implantation of differentials in 21 contaminated trials confirmed the efficiency of 11 resistance genes against the BaYMV-2/BaMMV complex. To monitor BaYMV and BaMMV resistance for registration in the National List real-time PCR appears more efficient than dCAPS. These findings will help breeders achieve sustainable resistance