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It is generally admitted that durum wheat pasta quality is greatly influenced by both protein content and composition. Durum wheat crops need high nitrogen inputs to produce grains with protein content required by manufacturers. With increasing fertilizer price and facing new environmental constraints, farmers have to modify their practises. Modifying practices is not always sufficient to maintain a high yield level with acceptable protein content so the need to create cultivars with better nitrogen use efficiency becomes necessary. The objective of breeders is now to create new durum wheat cultivars able to grow up with limited nitrogen intake and to remobilize efficiently nitrogen from vegetative organs of the crop to grains during filling with the need to fulfil quality criteria required by pasta making industries. In this context a study was undertaken by French breeders in association with public research, development organizations and pasta manufacturers in order to define minimal requirements in terms of protein quantity and quality to produce pasta able to satisfy consumers. Eight cultivars were grown during two years in the south of France with nitrogen intakes varying from 0 to 360 units. At harvest, grain characteristics (thousand kernel weight, specific weight, yellow berry…) were determined. Protein content and composition measured by size exclusion-chromatography were also evaluated along with gluten index, SDS sedimentation test. Semolina were produced and used to make spaghetti and dough discs. Pasta quality was evaluated through different measurements (texture, color, smoothness and appearance, cooking losses…) before and after cooking. A statistical analysis was then performed and shown that it is possible to reduce nitrogen fertilization to some extent without affecting dramatically pasta quality. Data also provide useful information to reconsider tests used during breeding programs to predict the end use quality of durum wheats.

Use of intergeneric crosses in cereals and in particular for increasing the genetic diversity of triticale. 9. International Triticale Symposium

Afin de lutter contre deux maladies préoccupantes pour la culture du triticale, l’oïdium et la fusariose sur épi, nous avons étudié à la fois des approches agronomiques et génétiques. Concernant l’oïdium, des associations variétales ont été testées durant trois années. Par ailleurs, les virulences de populations naturelles du pathogène Blumeria graminis du triticale ont été déterminées à l’aide d’hôtes différentiels de blé au stade 2-3 feuilles. Puis une collection de triticales a été caractérisée par la même technique d’une part et aussi à l’aide de souches isolées d’autre part. Ces tests n’ont pas permis d’identifier les différents gènes de résistance présents chez les triticales mais ils ont apporté de nombreuses connaissances utiles. Concernant la fusariose, les analyses de flore ont montré que cette maladie du triticale est principalement causée par Fusarium graminearum et Microdochium spp en France, comme pour les blés. Pour l’accumulation de la mycotoxine déoxynivalenol (DON), de même que pour le blé tendre, les facteurs de risques les plus importants ont été les précédents maïs ou sorgho et l’absence de travail du sol. Sur la collection de triticale, évaluée en conditions semi-contrôlée à l’aide d’une souche de F. graminearum, la notation des symptômes a été grandement facilitée par la mise au point d’une méthode d’imagerie associée à la création d’un logiciel Fusanote®. Cependant, les interactions génotype x année ont été fortes. Pour les deux maladies, une recherche de QTL sur plusieurs populations a permis d’identifier quelques marqueurs intéressants. En tenant compte des informations et outils précédents, la collection de triticale a été génotypée pour les marqueurs jugés pertinents. Enfin, des blés et seigles intéressants ont été croisés et ont permis d’obtenir de nouveaux triticales primaires potentiellement résistants qui serviront de géniteurs dans les programmes de sélection triticale et apporteront de la diversité., To face powdery mildew and Fusarium Head Blight (FHB) on triticale, agronomic and genetic approaches were studied. Concerning powdery mildew, cultivars mixtures have been tested for three years. Virulence of natural triticale powdery mildew populations was determined using a set of wheat differential hosts at seedling stage. Then, a collection of triticale was characterized in the same conditions and also with isolated powdery mildew strains. These tests did not make it possible to identify resistance genes carried by triticale; however they provided useful knowledge. As regards FHB, flora analysis showed this disease on triticale to be due mainly to Fusarium graminearum and Microdochium spp in France, similarly to wheat. For deoxynivalenol accumulation, agronomical main risks were the noA. tillage and corn or sorghum as previous crop. For triticale collection characterization with F. graminearum in semi-controlled conditions, new imagery method and Fusanote® software were helpful; however, cultivar x year interactions were strong. For both diseases, QTL analysis performed on three populations revealed some possible markers. Taking into account these results for powdery mildew and FHB, the collection was genotyped and new primary triticales were created by crossing wheat and rye, for breeding programs.

Renforcer les résistances du triticale à la fusariose par l’intégration de leviers génétiques et agronomiques. Séminaire du Comité Scientifique du CTPS

Caractérisation de génotypes maintenant une haute qualité technologique sous fertilisation réduite. Séminaire scientifique CTPS

Environmental rules and fertilizer price increase have pushed farmers to reduce nitrogen fertilization applied to the durum wheat crops. In order to optimize nitrogen application, cultivation practices such as splitting were promoted. These practices are not always sufficient to maintain elevated yield and grain quality required by milling and pasta making processes. The need to create cultivars with better nitrogen use efficiency is essential. Currently, for cultivar registration in the French national list, varieties are not tested under reduced fertilization conditions and it appears difficult to detect those which have the capacity to better use nitrogen. The objective of breeders is now to create new durum wheat cultivars able to grow up with limited nitrogen intake and to remobilize efficiently nitrogen from vegetative organs of the crop to grains during filling with the need to fulfil quality criteria required by pasta making industries. To achieve this goal a study was carried by French breeders associated with public research, development organizations and industrials in order to define minimal requirements in terms of protein quantity and quality to produce pasta able to satisfy consumers. Eight cultivars were grown during two years in the south of France with nitrogen intakes varying from 0 to 360 units. At harvest, grain characteristics (thousand kernel weight, specific weight, yellow berry…) were recorded and milling value was assessed with a micromill. Protein composition measured by chromatography and content were also evaluated along with gluten index, SDS sedimentation, tenacity. Semolina were produced and used to make pasta on a pilot plant. Pasta quality was appraised by different tests before and after cooking. A statistical analysis was then performed and shown that it is possible to reduce nitrogen fertilization to some extent without affecting dramatically pasta quality. Data also provide information useful to reconsider registration tests.

Environmental rules and fertilizer price increase have pushed farmers to reduce nitrogen fertilization applied to the durum wheat crops. In order to optimize nitrogen application, cultivation practices such as splitting were promoted. These practices are not always sufficient to maintain elevated yield and grain quality required by milling and pasta making processes. The need to create cultivars with better nitrogen use efficiency is essential. Currently, for cultivar registration in the French national list, varieties are not tested under reduced fertilization conditions and it appears difficult to detect those which have the capacity to better use nitrogen. The objective of breeders is now to create new durum wheat cultivars able to grow up with limited nitrogen intake and to remobilize efficiently nitrogen from vegetative organs of the crop to grains during filling with the need to fulfil quality criteria required by pasta making industries. To achieve this goal a study was carried by French breeders associated with public research, development organizations and industrials in order to define minimal requirements in terms of protein quantity and quality to produce pasta able to satisfy consumers. Eight cultivars were grown during two years in the south of France with nitrogen intakes varying from 0 to 360 units. At harvest, grain characteristics (thousand kernel weight, specific weight, yellow berry…) were recorded and milling value was assessed with a micromill. Protein composition measured by chromatography and content were also evaluated along with gluten index, SDS sedimentation, tenacity. Semolina were produced and used to make pasta on a pilot plant. Pasta quality was appraised by different tests before and after cooking. A statistical analysis was then performed and shown that it is possible to reduce nitrogen fertilization to some extent without affecting dramatically pasta quality. Data also provide information useful to reconsider registration tests.

International audience

Powdery mildew has emerged on triticale in the early 2000s in many locations, probably due to a host range expansion of the wheat formae speciales, Blumeria graminis f.sp. tritici. Many triticale cultivars are highly susceptible to powdery mildew, mainly in seedling stage, revealing a probably narrow genetic basis for powdery mildew resistance genes (Pm). Moreover, as Blumeria graminis is an obligate biotrophic fungus, it is very time consuming and difficult to maintain powdery mildew isolates for a non-specialized laboratory and populations can evolve. In order to identify wheat Pm genes efficient against natural populations of powdery mildew, wheat differential hosts and triticale seedlings were inoculated below susceptible triticale crop naturally contaminated by mildew, in several locations and several years. Symptoms on seedlings were measured after approximately two weeks of incubation in favorable fungus growth conditions. According to these data, we classified the Pm genes presents in our wheat differential hosts set in 3 classes: Pm already overcame by triticale powdery mildew, Pm having variable effects and Pm still efficient against triticale mildew. Data on triticale seedlings allowed us to identify some few triticale cultivars resistant to Blumeria graminis in seedling stage. We will try to identify Pm genes present in those cultivars next year by testing them with the characterized isolates of powdery mildew from Gent University. Nevertheless, interspecific crossing of wheat, resistant to powdery mildew in seedling stage, and rye have been initiated to introduce potentially interesting genes for resistance in triticale.

National audience; Genetic improvement of crops is feasible only if breeders have at their disposal a sufficient pool of variability. In the case of bread wheat which is allohexaploid (2n=42, AABBDD), intraspecific variability has already been extensively exploited. Even if genetic progress is still possible, enlargement of variability available is crucial for breeders. Possibly, the best solution is to exploit wheat diploid progenitors and tetraploid wheats. Aegilops tauschii (2n=14, DD) is among the three progenitors the one with the highest potential. Indeed, its genome has full homology with the wheat D genome and it displays large genetic variation since it is adapted to a range of continental-type habitats.[br/]Synthetic wheats derived from hybridization between tetraploid wheats and accessions of [i]Ae. tauschii[/i] were produced by Club5 and INRA. The objective of the project was to carry out assessment of synthetic wheats and introduce [i]Ae. tauschii[/i] genetic diversity conferring novel traits in adapted wheats.Significant outcomes concerned i) large variability of grain storage proteins which are involved in baking quality and ii) selection in the progeny of hybrids between synthetic wheats and elite wheats of genotypes adapted to low input farming. These genotypes with a yield performance equal to or higher than check cultivars in low input farming displayed very high levels of resistance to diseases. Nevertheless they were late, tall, susceptible to lodging and had a relatively low Chopin alveographvalue (W).; L'amélioration génétique ne peut être envisagée que si les sélectionneurs disposent d'un réservoir de variabilité suffisant. Dans le cas du blé tendre qui est allohexaploïde (2n=42, AABBDD), la variabilité intraspécifique a déjà été largement exploitée. Même si des progrès génétiques sont encore possibles, il est urgent d'accroître le potentiel de variabilité disponible du blé. La meilleure solution est l'exploitation de ses progéniteurs et des blés tétraploïdes. [i]Aegilops tauschii[/i] (2n=14, DD) est parmi ses trois progéniteurs diploïdes celui qui présente le plus d'intérêt. En effet son génome présente une homologie complète avec le D du blé et sa variabilité génétique est supérieure à celles des deux autres progéniteurs : [i]Triticum monococcum[/i] et[i] Ae. speltoides.[/i]Des blés dits synthétiques (2n=42, AABBDD) issus de l’hybridation entre des blés tétraploïdes et accessions d’[i]Ae. tauschii[/i] ont été créés par l’INRA et le GIE Club5. L'objectif du projet était de poursuivre leur évaluation et introduire de l’information génétique d’[i]Ae. tauschii[/i] conférant des caractères nouveaux d’intérêt agronomique dans du matériel élite de blé tendre.Les résultats les plus significatifs concernent i) la très grande variabilité des protéines de réserve du grain dont le rôle est primordial dans la qualité boulangère et ii) la sélection dans la descendance d’hybrides entre des blés synthétiques et des blés tendres Elite de géniteurs adaptés à des conduites en intrants réduits. Ces géniteurs dont le niveau de rendement est égal ou supérieur à celui des variétés actuelles en conduite ‘Faibles intrants’ présentent un très bon niveau de résistance aux maladies. Néanmoins ils sont tardifs, hauts, sensibles à la verse et ont une force boulangère (W) relativement faible.

Face au problème récent qu’est l’apparition de l’oïdium sur l’espèce triticale, un programme impliquant sélectionneurs, recherche publique et institut technique a été conduit de 2008 à 2011 avec le financement du Ministère de l’Agriculture. Il avait pour objectifs de suivre l’évolution de la maladie, d’avoir une meilleure connaissance des virulences de l’agent pathogène, de rechercher des sources de résistance à l’oïdium variées qui permettront de créer de nouvelles variétés résistantes, et de mieux comprendre la génétique de la résistance à l’oïdium et en particulier des résistances présumées durables. Nous savons que l’agent pathogène provient de la forme spéciale attaquant le blé tendre. Nous avons identifié des gènes du blé tendre qui semblent efficaces contre les souches attaquant le triticale (Pm1-allèle de Chopin, Pm3d, Pm4, MlTo, MlSo notamment et dans une moindre mesure MlSi2, MlTa2 et Mld). Nous avons identifiés des génotypes résistants (ressources génétiques et matériel issu de nouveaux croisements blé x seigle) et des marqueurs moléculaires microsatellites potentiels soit en partant de bibliographie, soit en étudiant des populations de triticale en ségrégation. Il reste cependant de nombreux aspects à approfondir., To face the recent emergence of powdery mildew on triticale species, a collaborative programme between breeders, public research and technical institute has been conducted from 2008 to 2011 with financial support of French Agriculture Ministry. The aims were: a survey of disease evolution, a better knowledge of pathogen virulence, finding new and varied resistance genes to create new resistant varieties, a better understanding of genetic resistance and especially durable resistance. Now, we know that powdery mildew on triticale came from bread wheat formae speciales. We identified bread wheat genes that seem to be efficient against triticale powdery mildew (Pm1-Chopin’s allele, Pm3d, Pm4, MlTo, MlSo especially and in a lesser extend MlSi2, MlTa2 et Mld). We identified resistant genotypes (genetic resources and material derived from new wheat x rye crosses) and potential molecular SSR markers from bibliography and from segregating triticale populations. Nevertheless, several points remain to be investigated more deeply.

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National audience; Depuis la première réforme de la politique agricole commune en 1992, les grandes cultures (céréales, oléagineux et protéagineux) sont confrontées à une nouvelle donne : baisse importante, de l'ordre de 40%, du prix de vente ; quasi-stabilité du prix des intrants chimiques ; découplage croissant des aides directes de soutien des revenus ; critiques de plus en plus vives des méthodes de production trop intensives et donc ayant des effets négatifs sur l'environnement. Dans ce contexte, il convient de se poser la question de l'optimalité des couples "variétés productives-itinéraires techniques intensifs" utilisés majoritairement à ce jour. Plus que la seule désintensification des itinéraires techniques à variétés inchangées, il convient surtout d'examiner dans quelle mesure le choix de nouvelles variétés multi-résistantes et d'itinéraires techniques plus économes en intrants chimiques correspondraient, ou non, au nouvel optimum économique pour l'agriculteur. L'objet de l'article est donc de comparer différents couples "variété-itinéraire technique" en utilisant pour cela les résultats du réseau d'essai "itinéraires techniques pour des variétés rustiques de blé tendre", créé en 1999 à l'initiative de l'INRA, des sélectionneurs du groupement d'intérêt économique (GIE) "Club des 5" (C.C. Benoist, Florimond Desprez, Serasem et Verneuil Nickerson) de l'ITCF, devenu depuis Arvalis-Institut du végétal.