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International audience; Developing sustainable apple cultivation is based on both a better knowledge of tree architecture and physiology in relation to fruiting, and on how the tree interacts with its abiotic and biotic environments. Improving knowledge in these domains is crucial to take into account the societal demand towards less input-dependent orchards. This chapter provides an overview of apple tree growth and fruiting, exploring the bases for sustainable apple training and pruning management. The chapter also challenges the current apple production agroecosystem and looks ahead to future research trends in this area.

International audience; Agricultural research has to tackle complex questions such as the design of sustainable cropping systems. System experiments are innovative approaches to address this challenge and a framework to iteratively design annual cropping systems has been proposed by Debaeke et al. (2009). However, specificities of some other cropping systems are not considered. Orchards are complex perennial agroecosystems formed of grass and tree layers aiming at the production of fresh fruit that require specific design and management over space and time. To identify orchard specificities and adapt the design framework to such perennial systems, we used two case studies of orchards aiming at decreasing pesticide use in temperate (apple, system experiment) and tropical (citrus, on-farm network) fruit productions. Specificities to take into account in the design framework are: (1) the spatial heterogeneity of the orchard with grass and tree layers, and tree rows and alleys; (2) the succession and interrelations among a young unproductive and then a productive stage; (3) the permanency of the fruit-tree crop constraining the management of soil fertility, (4) ground cover and (5) pest control, especially for pests that complete their lifecycle in the orchard and can build up important populations or inoculum across years. This is especially true in tropical areas where there is no dormant season. (6) Conversely, the permanency of the orchard habitats facilitates the sowing, planting or conservation of plant assemblages (e.g., ground covers, lining hedgerows) to enhance conservation biocontrol and/or compete weeds, provided non-disruptive practices are applied. Because of their longevity, orchards contribute to foster both plant-mediated (e.g., bottom-up) and natural enemy-mediated (e.g., top-down) processes in the foodweb to avoid direct measures against pests. Interactions among the orchard life stages, spatial and functional dimensions and practices need to be explicitly considered to optimize the efficiency of the system as a whole. Using the generic framework proposed by Debaeke et al. (2009) to design annual cropping systems, our framework includes adaptations to account for orchard specificities: (i) Agronomic objectives have to be fixed for each orchard stage; (ii) The cultivar choice and the composition and spatial arrangement of plants within the orchard are key elements to provide the expected services in the long term. This entails to include an additional step of perennial spatial design; (iii) Within-time and −space interactions have to be considered in the decisional system; (iv) Evaluation has to consider all the orchard stages in the global impact or performance, to account for carry-over effects and possible ‘paybacks’ of a given stage or period to the orchard whole lifetime. Last, to handle such complex interactions, design needs knowledge from many stakeholders in the food system (growers, advisors, scientists etc.) and requires more and renewed interactions among those stakeholders in a co-design process.

Pesticides represent the major input in pome fruit across Europe. They are mainly used on a calendar-based approach in order to control a large number of pests and diseases causing both direct and indirect losses. This situation has stimulated research for innovative tools and methods for pest management and the PURE project (www.pure-ipm.eu) organised a biointensive framework to demonstrate that several solutions are now available but they need to be properly transferred to the growers to be applied on a large scale. This paper presents the experience of the PURE project across demonstration orchards in different countries. The aim was to develop a multicriteria evaluation to help more clearly define the advantages and disadvantages of applying innovative Integrated Pest Management (IPM) systems, for different pests (pear psylla and apple codling moth) and diseases (pear brown spot and apple scab) on pome fruit, compared to standard IPM (i.e. currently adopted IPM system). The multicriteria approach permitted to assess environmental risks, economic effects and sustainability impact for each of the innovative systems tested. This multicriteria assessment showed that, in general, innovative performed better than standard for environmental quality and provided similar yield and pest management without any significant extra costs.

International audience; The impact of a cultivar mixture within the rows including the cvs Melrouge (low susceptibility to scab) and Pitchounette (Rvi6 resistant) was assessed during 2008e2009 in an organic apple orchard located in Rhône Valley (Drôme, France), on three important pests and diseases: scab, powdery mildew and rosy apple aphid. In this area, the resistance of Rvi6 gene was effective since the orchard plantation in 2004. The impact of the cultivar mixture was assessed per se, but also associated with sanitation practices to decrease the primary inoculum of scab and mildew, and compared to disease development on pure stands of Melrouge. The cultivar mixture showed a good efficiency to decrease the scab incidence on leaves and fruits; a significant effect on scab severity was observed in 2009 for the cultivar mixture plus sanitation practices. Our data confirmed the different susceptibility levels of the two cultivars for powdery mildew. Against powdery mildew, a favourable effect of cultivar mixture, at the condition it is associated with sanitation, was observed in case of a moderate level of the disease (2008). For rosy apple aphid, a favourable effect of cultivar mixture was observed on Melrouge in 2008 when Pitchounette has a good resistance level. In the context of organic production, the impact of the cultivar mixture seemed favourable for the control of the three pests and diseases.

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitières; International audience; Ideotypes are a popular concept for plant breeders, who designate as such the ideal combinations of traits in a particular genotype to reach a pre-set production objective within a given socio-economic context. The historical, ‘genetic’ view of ideotypes has been more recently extended to cover the design of plant genotypes for specific cropping systems (the ‘agronomic’ view), or even the ideal combination of parameters, identified from formal or simulation modeling, to a specific agronomic problem (the ‘modelling’ view). These different forms of ideotypes in turn lead to different strategies for breeding plants. This paper will briefly describe, analyse and discuss some applications of these ideotype views, using the specific case of architectural traits of plant and crop canopies to limit the epidemic development of pests and diseases in crops. It is not intended to be an exhaustive and objective review of the existing literature on plant ideotypes, but rather to express as an ‘opinion’ paper the views discussed and elaborated among participants to the EpiArch network.

The French apricot production is located in the South-Eastern part of the country and focused both in the Rhone valley and close to the Mediterranean Sea. The north of the Rhone valley is characterized by a continental climate while the southern region (Rhone valley and Mediterranean area) is under warm typical Mediterranean climate. Obviously apricot fruit production depends on a specific panel of cultivars in each area of cultivation due to economic and adaptation constraints. In order to enlarge the panel of cultivars to be developed by the growers in each region an integrated breeding program is developed at a national level in France with the participation of INRA, CENTREX and CEP INNOVATION. The main goals of the breeding program are: the elaboration of cultivars suitable for a durable production (including resistance to pests and disease), production regularity (including self-fertility and quality of the flowers), and fruit quality (including taste, attractiveness, and suitability for the transport). The evaluation phase is organized in the 3 main areas of production (Perpignan, Nimes, Valence) and follows 3 complementary evaluation stages (i) observation of the hybrid on its own roots; (ii) evaluation of the best hybrids after grafting in the 3 main areas; (iii) assessment of the agronomic and commercial interest of the 'elite' accessions in small orchards. The main results issued from this program are presented: 8 registered cultivars, 4 new selections under registration, and the first PPV resistant cultivar 'Aramis' ® 'Shamade'.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Watersprout occurrence and growth were investigated over a two-year period in an early maturing peach cultivar (Alexandra) under different intensities of dormant pruning for fruited and defruited trees. A preliminary study focused on identifying the laws that determine the probability of presence and occurrence of watersprouts in relation to watersprout-bearing shoot (WBS) length. The increase in watersprout probability of presence and occurrence resulting from greater WBS length illustrated the high capacity of peach for sprouting. Watersprout lengths were measured, as well as the lengths of young shoots, one-year-old fruit-bearing shoots (FBSs) and older branches considered as WBS in order to evaluate total shoot growth within the tree. Watersprout number and total length tended to be higher under severe dormant pruning and in fruited trees than under light dormant pruning and in defruited trees. This stimulation of watersprout length appeared to compensate for the concomitant lower total length of young shoots, resulting in a constant overall vegetative growth rate for the whole tree. In the second year of the experiment, watersprouts were either removed by summer pruning or not in order to evaluate watersprout incidence on the rest of the tree. After light and severe watersprout removal (WSR), the annual diametrical growth of FBS tended to be higher and lower, respectively, compared to trees not submitted to summer pruning. Light WSR might favour light interception in the centre of the canopy, thus improving assimilate production and allocation to FBS, whereas severe WSR could prevent carbohydrate export from watersprouts to FBS. Under our conditions, the limit at which WSR intensity became detrimental for FBS diametrical growth appeared to be after approximately 75% of the watersprouts were removed. Severe WSR appeared likely to improve fruit diameter, whereas it had no significant impact on the percentage of soluble solids

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; In this paper, QualiTree, a fruit tree model designed to study the management of fruit quality, and developed and described in a companion paper (Lescourret et al. in Trees Struct Funct, 2010), was combined with a simple light-interception sub-model, and then parameterised and tested on peach in different situations. Simulation outputs displayed fairly good agreement with the observed data concerning mean fruit and vegetative growth. The variability over time of fruit and vegetative growth was well predicted. QualiTree was able to reproduce the observed response of trees to heterogeneous thinning treatments in terms of fruit growth. A sensitivity analysis showed that the average seasonal growth rates of the different organs were sensitive to changes to the values of their respective initial relative growth rates and that stem wood was the tree organ the most affected by a change in the initial relative growth rates of other organs. QualiTree was able to react to simulated scenarios that combined thinning and pest attacks. As expected, thinning intensity and the percentage damage caused by pests significantly affected fruit yield and quality traits at harvest. These simulations showed that QualiTree could be a useful tool to design innovative horticultural practices

INRA, CENTREX and CEP INNOVATION are developing new apricot cultivars for French growers with particular attention paid to consumer's expectations. The main objectives of the related breeding programme are: production regularity, fruit quality and attractiveness. Their evaluation is based on a multilocal and pluri-annual set of trials located in the three major French areas of cultivation and organised as a 3-stage-evaluation: (i) observation of the seedlings on their own roots (ii) evaluation of the best grafted selections in the 3 main areas, (iii) assessment of the agronomic and commercial interest of the 'elite' accessions in small commercial orchards. At the end of the selection process two recent main types of cultivars have been introduced: - Ten new cultivars able to enlarge the harvesting season by 'conventional' type of fruit ('Soledane', 'Solimar'@, 'Candide', 'Bergerval'@, 'Bergarouge'®, 'Royal Roussillon', 'Vertige', 'Fantasme'@, 'Helena du Roussillon'®, 'Frisson'); - Three new fruit-type apricots characterized by a stark red blush covering 80% of the fruit shape, developed under the same trademark, 'Rubisco'@ (Ravival, Ravilong and Ravicile).

International audience; In gene-for-gene interactions, avirulence genes interact, directly or not, with host resistance genes, triggering several defense mechanisms and resulting in no disease development. This kind of interaction was shown to occur in many host-pathogen relationships, including the one between Malus * domestica and Venturia inaequalis, the causal agent of apple scab. In the specific interaction between the host cultivar 'Golden Delicious' and V. inaequalis race 7, both the resistance gene Vg and the avirulence gene AvrVg have been identified and their map position determined in the host and in the pathogen genome respectively. Focusing on the fungal avirulence gene AvrVg, we constructed a genomic library of an AvrVg avirulent isolate and performed a chromosome walking, isolating and sequencing a 330 kb genomic region carrying this gene. Four different in silico gene predictions were performed on the genomic sequence resulting in a total of 169 genes grouped in 60 coding regions, some predicted by all four predictions to encode for the same identical protein and other regions where differences between the different predictions were found in the splicing sites. A second analysis was performed by software, allowing the identification of 40 regions coding for genes predicted to be secreted extracellularly, either by signal peptide or by non-classical secretion, these being the most common feature among avirulence genes. The next step toward identification of the real avirulence gene is the investigation of the expression of such candidate avirulence gene identified in silico as well as the examination of their possible alleles in virulent isolates. The results of the in silico gene prediction in the AvrVg region and preliminary results of candidate avirulence gene expression experiments will be presented.

International audience; Different irrigation regimes were performed on container-grown early-season peach trees (cv. Alexandra) during stage III of fruit growth. In the first experiment, three water treatments were applied: T1, control irrigation; T2, light water restriction; T3, high water restriction. In the second experiment, T4, a light water restriction, was compared to T5, the same total amount of water as T4 but with alternating periods of water withholding and subsequent re-irrigation. Compared to T1 and T2, leaf photosynthesis was limited under T3. Fruit yield and quality did not differ between T1 and T2, while fruit yield, average weight and percentage in the higher commercial grade decreased and total soluble solids (TSS) increased under T3, compared to T1 and T2. Comparing T5 to T4, yield, fruit firmness and average weight did not vary, but heterogeneousness of fruit diameter and TSS at the lower fruit grade tended to be higher. Peach sensitivity to brown rot was likely to decrease under T3 compared to T1 and T2. Peach water loss and brown rot incidence after contamination in conidial suspensions were enhanced under T5 compared to T4, implying that re-irrigation after water withholding should be avoided in order to limit brown rot incidence.

Brown rot (BR) caused by Monilinia spp., has been an economic problem for the stone fruit market due to the dramatic losses, with the biggest losses mainly during the postharvest period. There is much literature about basic aspects of Monilinia spp. infection, which indicates that environment significantly influences its occurrence in the orchard. However, progress is needed to sustainably limit this disease: the pathogen is able to develop resistance to pesticides and most of BR resistance research programs in plant models perish. Solving this problem becomes important due to the need to decrease chemical treatments and reduce residues on fruit. Thus, research has recently increased, exploring a wide range of disease control strategies (e.g. genetic, chemical, physical). Summarizing this information is difficult, as studies evaluate different Monilinia and Prunus model species, with diverse strategies and protocols. Thus, the purpose of this review is to present the diversity and distribution of agents causing BR, focusing on the biochemical mechanisms of Monilinia spp. infection both of the fungi and of the fruit, and report on the resistance sources in Prunus germplasm. In this review, we comprehensively compile the information currently available to better understand mechanisms related to BR resistance.

In horticulture, stringent market requirements regarding the visual quality of products have led to the intensive use of pesticides worldwide. The immediate need for environmentally-friendly pest control, already embodied in the development of IPM, is exacerbated by pressing social demands and policy contexts. At the same time, the scientific community is increasingly interested in new disciplinary branches and concepts such as agroecology, ecosystem services and ecological intensification that create an opportunity to develop new approaches to pest control research. A conceptual framework is presented that addresses the issue of the ecological control of pests in horticulture. It is based on key ecological concepts- trophic network, biotic interactions, niche and dispersal. This framework stresses the trophic and nontrophic interactions that occur between the components of three trophic levels plants, pests and natural enemies. It highlights the effect of agroecosystem management on these components, namely on the niche dimensions and dispersal of pests and enemies, and its consequences on pest control. This management includes the addition of plant or animal biodiversity, as well as practices to control the functioning of this planned biodiversity. Examples taken from greenhouse and orchard studies illustrate the salient points of the conceptual framework. This approach has a high potential in horticultural systems where there is the possibility to combine various sources of biodiversity and various technical levers. However, more knowledge about the functioning of target ecological networks is required to improve its robustness. In addition, a major current challenge that makes this approach more difficult is the necessity to consider the ecological control of pests within a set of multiple agroecosystem services to be managed.

Brown rot can lead to considerable fruit losses in peach orchards and cultural practices likely to contend this major disease have to be promoted. In order to limit peach brown rot incidence in a three-year-old mid-season maturing peach orchard of the cultivar ’Ruby Bright’, four combinations of irrigation and soil management treatments were assessed: conventional (Conv) irrigation (I) and soil management (S) (ConvI+ConvS); modified (Mod) irrigation and soil management (ModI+ConvS); conventional irrigation and modified soil management (ConvI+ModS); and modified irrigation and soil management (ModI+ModS). Conventional irrigation and soil management in the tree row consisted of irrigation scheduling using tensiometer readings and herbicide use, respectively. Modified irrigation and soil management in the tree row consisted of water deprivation during stage III of fruit development and ground cover with white clover, respectively. For four consecutive years (2010–2013), in the conditions of the Middle Rhone Valley in France, the lowest and highest brown rot incidence were detected under (ModI+ModS) and (ConvI+ConvS), respectively, whereas brown rot incidence under (ModI+ConvS) and (ConvI+ModS) was intermediate. This lower brown rot incidence under the modified treatments occurred from one to two weeks before fruit maturity and was still observed for several days in post-harvest storage. Ground cover with white clover was shown to limit water availability in the soil after heavy rainfall compared to bare soil, probably limiting peach growth variations, well-known as a possible source of detrimental microcracks at the fruit surface. This suggests that under our conditions appropriate cultural practices, water deprivation and a clover crop cover in the tree row possibly decrease peach disease sensitivity, which might lead to the reduced use of pesticide sprays to control brown rot in the orchard.

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitières; National audience; The progression towards sustainable horticulture is usually associated with scientific and methodological breakthroughs. As a consequence, the innovation processes in the fields of biology and ecology and their agronomic implementation are increasingly recognized as main drivers to improve horticultural systems. At the same time, a horticultural system cannot be designed without good knowledge of the social and economic contexts in which it is embedded; it has to be considered as an integrated social-ecological-agrosystem. For example, the cross-knowledge derived from interdisciplinary research constitutes the backbone for building ecologicallybased crop ideotypes and cropping systems, including genetics, agronomy and social environmental levers and constraints. Designing new horticultural systems in such a systemic framework is also relevant to develop and better implement knowledge exchange among agents. This strong intertwining of the different research fields poses new challenges. There is a need for more participatory research and scaling-up to achieve adoption of innovations along the horticultural chain. Thus, the former linear and top-down scheme, i.e., from basic science to applied science and fieldwork, is now reconsidered and the design of innovative agricultural production systems is viewed as an integrated, interactive and participatory process where agents are dynamically interacting. The new challenge is to better combine the detailed knowledge typical of the dominant reductionist paradigm generally oriented towards the “one-size-fits-all” objective and the paradigm of complexity where the “custom-fit” approach predominates. Progressing towards these frameworks of knowledge and relationships among agents poses epistemological questions about interdisciplinarity and hybridization between scientific and non-scientific (advisor, grower) knowledge.

The effect of codling moth Cydia pomonella management on the arthropod community and on the natural enemies of pests was analysed from 2001 to 2003 in both the tree canopy and the grass cover of three experimental apple orchards under different management strategies: supervised control of codling moth based on chemical protection (C); mating disruption against codling moth, including additional pesticides when needed (MD); and microbiological control with granulosis virus in an organic orchard (O). The three management systems differed in terms of biomass and functional organisation of arthropods. Number of individuals tended to be higher in the O orchard, and the complex of beneficial arthropods of this orchard was based on polyphagous predatory arthropods (including earwigs) in both studied habitats. Conversely, parasitoid Hymenoptera constituted the prevailing group in the arboreal habitat of both the C and MD orchards. The highest diversity and evenness indices were unexpectedly measured in the C orchard. The richness of arthropods was the highest in the grass cover of the O orchard. The opposite was found in the tree canopy, the lowest values being measured in the arboreal habitat of this orchard. Depending on the year, the sampling period and the vegetation strata (apple tree canopy or grass cover), diversity and evenness indices measured in the MD orchard were either closer to the O orchard or to the C orchard.

International audience; French apricot production is located in the south-eastern part of the country, with a focused zone in the Rhone valley and close to the Mediterranean Sea. The north of the Rhone valley is characterized by a continental climate, while the southern region ( Rhone valley and Mediterranean area) is under a warm, typically Mediterranean climate. Obviously, apricot fruit production depends on the development of a specific panel of cultivars in each area of cultivation because of economic and adaptation constraints. In order to enlarge the panel of cultivars for growers of each region, an integrated breeding program has been developed at a national level in France with the participation of INRA, Centrex and CEP Innovation. The main goals of the breeding program are: the elaboration of cultivars suitable for durable production ( including resistance to pests and diseases), production regularity ( including self-fertility and quality of the flowers), and fruit quality ( including taste, attractiveness, and suitability for transport). The evaluation phase is organized in the three main French areas of production ( Perpignan, Nimes and Valence) with three complementary evaluation stages: ( i) observation of hybrids on their own roots ( ii) evaluation of pre-selections after grafting in the three main areas, and ( iii) 'elite' agronomic and commercial assessments in small orchards. A tough diagnosis, that includes biological, serological and molecular analysis, is conducted in parallel for assessing resistance to Plum pox virus ( PPV). The main results issued from this program are presented here, with 10 cultivars, including PPV-resistant Aramis (R) cultivars.

National audience

International audience; We studied dry matter partitioning to fruit by establishing different patterns of fruit distribution between and within main branch units (scaffolds) on early (cv. ‘Alexandra’) and late (cv. ‘Suncrest’) maturing cultivars of peach (Prunus persica L. Batsch). The desired fruit loads were obtained by differential thinning of scaffolds and the commercial crop-load per tree was maintained. Each tree had four main scaffolds, one of these scaffolds was lightly thinned (Highcrop scaffold), another one was heavily thinned (Low-crop scaffold) and the different fruit bearing stems (FBS) were alternately lightly thinned or heavily thinned in two scaffolds (Alternative-scaffold). Growth of fruits and of leafy shoots on all FBS were measured periodically from hand-thinning 30 and 50 days after full-bloom (DAFB) until harvest for cvs. ‘Alexandra’ and Suncrest, respectively.The mean fruit dry weight (DW) per FBS was strongly affected by fruit distribution between and within scaffolds in the late cv. ‘Suncrest’, indicating that branch autonomy was functional at the level of FBS in this case. In the early cv. ‘Alexandra’, mean fruit DW per FBS in each scaffold was similar, suggesting C-transfer between individual FBS. Branch autonomy could not be explained by fruit sink-strength being equal in both cultivars. In contrast to generative growth, vegetative growth was similar between scaffolds in both cultivars suggesting its independence from fruit sink removal.

National audience

Various nitrogen (N) and potassium (K) fertilizer rates and dates of application were assessed in an apricot orchard. High N fertilization enhanced vegetative growth, yield and average fruit weight and aggravated fruit pitburn incidence. Increasing K fertilization enhanced fruit soluble solids and colouring, but did not affect pitburn. Pre-harvest versus post-harvest applications of fertilizers did not influence vegetative growth, yield or average fruit weight, but tended to reduce fruit soluble solids and colouring. At all times of evaluation of pitburn, there was a positive correlation between fruit N content and pitburn incidence. Furthermore, for a given fruit N content, pitburn appeared to increase with the duration of conservation. A high fruit N content has to be considered as a main predisposing factor for pitburn in apricot. A negative correlation between pitburn incidence and fruit Ca content also was detected a week after harvest.

International audience; Research on innovative Integrated Pest Management (IPM) tools is done on station and on-farm in the PURE project. The idea is that IPM tools are tested under well-defined conditions in experimental orchards. Subsequently, they are tested in commercial orchards as part of a total IPM system where drawbacks and bottlenecks become clear. In subsequent on-station experiments the drawbacks or bottlenecks are solved and adjusted IPM tools are again tested in commercial orchards. We call this the "design - assessment - adjustment cycle". It is meant, together with co-innovation techniques, to promote uptake of innovative IPM tools by commercial farmers. For apple, new innovations are the use of exclusion netting against codling moth (Cydia pomonella), and the use of an antagonist against conidia of Venturia inaequalis. For pear, the overwintering inoculum of brown spot of pear (Stemphylium vesicarium) is reduced by antagonists and natural fertilisers, and the control of pear sucker (Cacopsylla pyricola) is promoted by natural enemies. For both apple and pear an innovative canopy adapted sprayer is used to reduce emissions and to further reduce pesticide use. Efficacy of these innovative IPM tools and IPM systems is assessed by the newly developed software for environmental effects: SYNOPS, for economic effects: PREMISE, and for overall sustainability, including economic, social and environmental aspects: DEXiPM-pomefruit. Results show that the overall sustainability of the conventional system is already high. Nevertheless, innovative IPM tools provided an improvement of environmental quality with an efficient control of diseases or pests. The cost for running the innovative IPM systems was often higher than the conventional system.

SummaryThe effects of covering fruit with clear plastic film during the final stage of rapid fruit growth were investigated on ‘Big Top’ nectarine and ‘Opal’ peach over three years. Covering fruit with plastic film modified the microenvironment around the fruit, particularly by increasing relative humidity and temperature during the day. These modifications influenced fruit development, fruit quality and leaf photosynthesis. Covering fruit with plastic film significantly reduced the dry matter content, either for fruit flesh or for total fruit, the content of total soluble solids in fruit fresh, and leaf photosynthesis under high light intensities (photosynthetically active radiation in excess of 1000.m.mol.m–2.s–1) as compared with uncovered control fruit. The relationship between photosynthetic rate and other leaf physiological responses showed that the depression of photosynthetic CO2 assimilation was related to reduced stomatal aperture and increased leaf temperature. It is suggested that the stomatal...

International audience

With the failure of conventional chemical control against the pear tree psyllid Cacopsylla pyri (L.) (Homoptera: Psyllidae), strategies have been developed to enhance natural arthropod enemies of this pest. Modifying the vegetation adjacent to pear orchards is one integrated pest management (IPM) practice that can increase the agroecosystem plant diversity, thus favoring a natural balance between pest arthropods and their enemies. Different plant species were examined as sources of beneficial arthropods for the pear orchard. Arthropod faunas were sampled in the pear tree (Pyrus communis L.) canopy, the ground cover, and in the hedgerow tree species surrounding the orchard. Inter-relationships between pear and hedgerow tree species were studied by Spearman's rank correlation. Ash trees and ivy display a diversified fauna that was correlated with the pear tree community, but not with each other. Their influence on pear tree fauna is different: ash trees host specific psyllids and gall midges (Diptera: Cecidomyiidae), providing food for beneficial pear arthropods and ivy acts as a shelter species for beneficial pear arthropods. Calculation of correlations between the faunas of non-crop and crop plant species appears as a useful tool for estimating the risk (correlation between phytophagous guilds) and benefit (correlation between beneficial guilds) of plants dedicated to environmental crop management. The following orchard ground covers were tested: (1) bare ground; (2) natural grass cover; and (3) sown ground cover. Multivariate analysis was performed to characterize ground cover arthropod communities. Natural ground cover and sown ground cover sheltered distinct arthropod communities; the natural ground cover beneficial fauna was characterized by spiders and the sown ground cover fauna was characterized by ants. The structure and numbers of the arthropod assemblages collected on pear trees from the three types of ground management were different. The main beneficial arthropods on pear tree were Anthocoridae (Heteroptera) and Miridae (Heteroptera) in the sown area; Empididae (Diptera) and Miridae in the natural ground cover area; and Forficulidae (Dermaptera) and Miridae in the bare ground area. Moreover, the sown ground cover favored a higher beneficial : phytophagous ratio to that in the pear tree canopy. These results imply that interactions are likely to occur between pear trees and hedgerow, and between pear trees and ground cover within the orchard agroecosystem. Manipulating beneficial arthropods through vegetal environment management using selected tree and grass species shows promise in optimizing pear orchard IPM.

The relationship between peach fruit (Prunus persica L. Batsch) composition and growth was studied in six cultivar-training-site-season combinations. Individual fruit growth and sugar and acid cont...

National audience

Regular-bearing in fruit trees ensures regular income for the fruit grower and is a main issue for orchard profitability. The relationships between vegetative growth and fruiting have been extensively analyzed on the sexually mature, i.e. adult, tree. However, there are scarce studies on the relationships between growth and flowering of the young tree and the fruiting pattern, i.e. regular vs. alternate bearing, of the adult tree. Our study was developed in the apple, which apart from its economic importance, is likely the most studied fruit species for architecture and fruiting. Twenty-four cultivars with contrasted architectures and fruiting patterns were chosen. Thanks to a principal component analysis, our study compared some architectural traits of these cultivars at the young stage, under minimal pruning and training, and the fruiting pattern of the same cultivars at the adult stage. In the latter case, data were obtained from an independent set of experts from various European regions. Three traits of the young tree were well related to the fruiting pattern of the adult tree: the level of recurrent flowering on the same lateral across consecutive years, i.e. bourse-over-bourse; the cessation of growth of the laterals, i.e. lateral extinction; and the percentage of flowering laterals among all functioning laterals on the one-year-old wood. High values of these three traits were positively related to regular bearing of the adult tree. We discuss the interest to integrate these traits in the definition of an apple tree ideotype for regular bearing that can be useful for an early diagnosis of regular bearing on apple trees in germplasm collections and in progenies.

Conventional agricultural systems have become more intensive and pesticide-dependent over the last few decades. The contamination of the environment by pesticides, the use of mineral fertilisers, and habitat loss in many agroecosystems have led to a drastic decrease in plant and animal biodiversity. Ecosystem services provided by functional biodiversity (e.g., pollination, biological pest control) have also been negatively impacted. Conservation biocontrol aims to preserve and promote natural enemies to enhance pest control, avoid pest outbreaks and reduce pesticide reliance. However, despite a consensus on the main underlying principles, intentional practical applications are still rare. It is assumed that the diversity of habitats and resources in agroecosystems enhances the diversity and/or effectiveness of the natural enemies of pests. In this article, we argue that organic farming (OF) provides a promising framework for increasing conservation biocontrol at field and farm scales in agricultural landscapes. We looked at most of the commonly used OF practices at different spatio-temporal scales and discussed their effects on pest populations, natural enemy communities and biocontrol in agroecosystems. Several OF management practices such as crop diversification, use of organic fertilisers, diversification of resource plants at the field or landscape scales and land-use management are examined in our review. We particularly focused on possible strategies to enhance pest control measures in two case studies (i.e., orchard and annual crops) and discussed how and at which scales such strategies should be implemented. In the end, we identified knowledge gaps and bottlenecks that, if resolved, would help to enhance conservation biocontrol and applications in OF systems that aim to maximise both bottom-up (through plants) and top-down (through natural enemies) processes.

UMR 1334 AGAP : Equipe AFEF ‘Architecture et Fonctionnement des Espèces fruitières’ ; Team AFFS ‘Architecture and Functioning of Fruit Species’ Contact: Sylvaine.Simon@avignon.inra.frPublication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; Plant architecture highly constrains pest infestation but is rarely considered in studies on plant–insect interactions. We analysed the relationships between apple tree architectural traits manipulated by tree training and within-branch development of Dysaphis plantaginea (rosy apple aphid, RAA),a major apple pest,during its multi- plication wingless phase in spring. We hypothesised that the degree of branching had an effect on RAA within-branch estation. In an experimental apple orchard, the infestation by aphid wingless forms was surveyed in two consecutive spring seasons within branches manipulated to design contrasted architectures differing in shoot numbers, shoot density and branching orders. Whatever the branch management system, aphid infestation was higher on long versus short, fruiting versus vegetative, and growing versus non-growing shoots. Either less infested shoots or less severe infestation were observed in the most branched system. A pattern of within-branch short-distance infestation was confirmed. Moreover, the number of branching points between two shoots exerted a high constraint on this infestation pattern. Beside possible trophic effects due to plant growth patterns already documented in the literature, a high degree of branching is likely to be a key-architectural trait to constrain within-branch aphid infestation. This opens new perspectives on the manipulation of branch architecture as a mean giving partial control of pests towards sustainable fruit production.

28. International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Organic Horticulture: Productivity and Sustainability Lisbon, Portugal, 2012/03/31; Plant architecture governs living conditions of herbivores. In fruit trees, the perennial structure is modulated by training and pruning which may affect pests. The effect of tree architecture manipulation on the development of the rosy apple aphid Dysaphis plantaginea (RAA) was investigated from 2002 to 2009 in apple orchards. The first step (2002-2005) consisted in comparing the Centrifugal Training system (CT) with extinction pruning (i.e., selective removal of spurs at bud-burst to favour light penetration and spur fruiting) to the Solaxe system (OS) with no extinction pruning. RAA infestation was significantly lower in CT trees 2 years out of 4. The hypothesis of a within-tree structural effect on RAA development was proposed beside possible microclimatic and mechanical (i.e., infested shoot removal) effects. In a second step (2007-2008) we investigated the relationships between the branch structure and RAA development in both training systems. In CT trees, branches displayed higher shoot orders compared to OS. Infestation dynamics presented similar patterns in both systems, but RAA spreading rate was lower in CT trees. These results suggested that the complexity of the aerial system due to higher branching orders affected insect movement within its habitat. In 2009 a glasshouse experiment with oneyear- old potted apple trees was carried out to test the combined effect of simplified architectures (1 vs. 2 extension shoots per tree) and of three nitrogen regimes on the development of RAA artificially set on the trees. There was no significant difference in aphid numbers at peak infestation between architectural treatments although RAA migration was earlier with 1 extension shoot. Moreover, a higher aphid population was shown for intermediate nitrogen regimes highlighting the pest response to trophic parameters. These experiments confirm the importance of tree training strategies in the management of orchard pests. They provide avenues to design sustainable orchard systems based on cultural methods giving partial control of pests.

International audience; Crop protection in general and apple crop protection in particular often rely on pesticides, although several alternative pest management measures are available. In this context European agricultural policy requires the implementation of Integrated Pest Management (IPM) by 2014. Within IPM, more than one strategy can be practiced but selecting the most sustainable strategy is difficult because it requires simultaneous assessment of multiple environmental and economic aspects or attributes. Here, we introduce the SustainOS methodology for sustainability assessment of orchard systems, and we evaluate its usefulness in a case study involving four crop protection strategies in apple orchards of five European regions. SustainOS is an iterative, multi-attribute approach for defining and rating the sustainability of crop protection strategies in comparative studies. It consists of a transparent system-description tool including context, target, and crop protection parameters. The parameters are used as input data for life cycle assessment, environmental risk assessment, and full-cost calculations. The various results from these quantitative assessments are used to generate a multi-attribute rating with respect to ecological and economic sustainability. We demonstrate how the quantitative results can be translated into rating classes. By applying the SustainOS methodology, we show that the ecological sustainability for all five regions can potentially be improved by implementing alternative crop protection measures currently available. We also report that, by increasing yield, yield stability, and fruit quality, implementation of IPM can improve the economic situation of apple growers. Because of its transparency, SustainOS facilitated the collaborative development and comparison of crop protection strategies for sustainable orchard systems by an international network of agronomists, economists, and environmental scientists.

International audience; The knowledge on the transmission of fruit quality traits has a great importance in order to optimize the inter-cultivar crosses design and to improve the efficiency of apricot breeding programmes. Four apricot progenies issued from different genetic origins were evaluated during two years; two apricot progenies cultivated in Avignon (France), one in Bologna (Italy), and other one in Murcia (Spain). Fruit quality characterization was based on physical measurements (fruit weight, colour, and firmness) and biochemical measurements (soluble solids content, and titratable acidity). Phenotypic datasets showed distribution of seedlings with regard to the parents, with a high variability for all analyzed quality parameters. An inter-annual variation was observed for the mean values of all the genotypes between the two years of the study, indicating the influence of the environmental conditions on fruit characteristics. Results indicated a quantitative inheritance of all quality traits in the apricot progenies indicating their polygenic nature. In general we observed in most cases a normal distribution of quality traits in the observed populations. However, in contrast to intermediate expected values between the parents, a large number of seedlings showed lower or higher values than their parents for many quality parameters. In this sense, results evidenced an extra genetic influence of the parents (the whole genetic background) on the transmission of fruit quality traits in apricot, which should be taken into consideration with inter-cultivar crosses design.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; We used eight microsatellite loci and a set of 20 aphid samples to investigate the spatial and temporal genetic structure of rosy apple aphid populations from 13 apple orchards situated in four different regions in France. Genetic variability was very similar between orchard populations and between winged populations collected before sexual reproduction in the fall and populations collected from colonies in the spring. A very small proportion of individuals (similar to 2%) had identical multilocus genotypes. Genetic differentiation between orchards was low (F(ST)

Estimation of demographic parameters is important for understanding the functioning of natural populations and the underlying ecological and evolutionary processes that may impact their dynamics. Here, we used sibship assignment methods to shed light on the local dynamics of codling moth females in eight orchards in a 90-ha domain near Valence, France. Based on full-sib inference among 1,063 genotyped moths, we estimated (1) the effective number of females that had offspring, (2) their fertility and (3) the distribution of their oviposition sites within and among orchards. The average number of females in all the orchards increased between the first (~130) and the second (~235) annual generations. The average fertilities of the females were similar at each generation according to the host plant considered (apple, pear, or walnut), but differed between commercial (~10) and non-treated (~25) apple orchards. Females mainly clustered their eggs on contiguous trees along orchard borders, but they also occasionally dispersed their eggs among different orchards independently of the cultivated host plants or the inter-orchard distances (up to 698 m) during the second annual generation. The mean distance between two oviposition sites was 30 m. Sibship estimates of both the effective number of females and the inter-orchard migration rates (~5%) were in agreement with the observed genetic differentiation among the eight orchards (0.006

Conventional agriculture is based on a high level of chemical inputs such as pesticides and fertilisers, leading to serious environmental impacts, health risks and loss of biodiversity in agrosystems. The reduction of pesticide use is a priority for intensively sprayed agricultural systems such as orchards. The preservation and promotion of biodiversity within orchards and their boundaries is therefore an issue to explore. Indeed, orchard systems contain high plant diversity and perennial multi-strata designs that provide wealthy resources and habitats to living communities such as beneficial organisms. Orchards thus offer favourable areas to maintain food-webs within the agrosystem, provided that favourable situations are not altered by cultural practices such as applying an excess of pesticides. Here, we analysed literature on the effects of the manipulation of plant diversity and habitats on the control of pests by arthropod and bird communities in apple, pear and peach orchards. Many investigations focus on the role of plant management to enhance biodiversity in orchards but only 22 research reports presenting 30 case studies were dedicated to the study of the ecosystem service provided by plant diversity for orchard pest control. The underlying mechanisms were seldom demonstrated, and the tested grass covers and tree assemblages aimed at favouring either the beneficial complex or only some beneficial species to control one or a few pests. The effect of plant management on pest control was mostly positive (16 cases) or null (9), but also negative in some cases (5). This finding reveals the difficulties of identifying selected plants or plant assemblages for the control of key pests. We conclude that further research is needed to identify the processes involved on different scales for biological control. Orchard systems should be re-designed to optimise ecosystem services provided by biodiversity.

Leaf Wetness Duration (LWD) is the main parameter involved in the apple scab development in apple orchards. LWD values can be inferred from weather conditions by solving a non-linear energy balance equation. Such energy balance equation is usually linearized leading to the Penman-Monteith equations. However this approximation leads to significant errors in the evaporative term and by consequence in the LWD computation. In this work, consequences of the use of the Penman-Monteith equations instead of the exact solution were firstly investigated on single droplets and compared to experimental values obtained in controlled and constant conditions. For these studies, the LWD is overestimated by 12% when Penman-Monteith equations were used. The ability of LWD estimate from the linearized energy balance equation to forecast risk infection of a leaf by V. inaequalis conidia was investigated. For some conditions, the error in LWD estimate by Penman-Monteith approached 6 h, leading to an incorrect risk assessment of apple scab development.

Efficient pest control using conservation strategies requires sound knowledge of the dynamics of the pest and its natural enemies (NE). But the role of natural regulation under natural conditions is not easy to prove. The rosy apple aphid (RAA) Dysaphis plantaginea is the most detrimental aphid in organic apple orchards. Our aim was to determine whether and to which point the abundance and composition of arthropod communities associated with aphid colonies affects RAA population dynamics. The present study, based on weekly observations of marked and infested apple shoots was carried out from April to June in 2008 and 2009 in one experimental insecticide-free apple orchard and four organic commercial orchards located in south-eastern France. NE populations were the most diverse (7.3 taxonomic groups for 50 shoots) and abundant (1.44 individuals per shoot) in the experimental orchard compared to organic orchards (3.8 groups for 50 shoots and 0.7 individuals per shoot). The large RAA populations per shoot (more by 1.7-fold) observed in two of the five orchards were presumably related to a lower number of NE (less by 1.9-fold) and a high abundance of ants (more by 6.2-fold). Among the main NE groups, syrphids arrived first, followed by coccinellids and earwigs. Parasitism rates, mainly due to Ephedrus sp. (Braconidae), were between 0.66% and 6.93%. Based on their precocity and abundance, syrphids appeared to be the most efficient group of NE under the study conditions. By surveying the same shoots weekly we could demonstrate that RAA population dynamics were strongly affected by the presence of NE. This predatory effect was however not sufficient to prevent damage to the apple trees. New management practices aimed at favoring natural regulation, especially augmentative approaches, need to be developed.

International audience; The Venturia inaequalis-Malus pathosystem was one of the first for which gene-for-gene relationships were demonstrated following the discovery of such relationships between Melampsora lini and flax by Flor in the 1950s. An understanding of these relationships forms the basis for monitoring pathotypes of V. inaequalis at the population level and is employed to assess the usefulness of resistance genes for breeding durable resistance to scab. These pathotypes are difficult to accommodate in the current system of nomenclature for V. inaequalis races where each new combination of avirulence alleles is assigned a simple numerical descriptor as its name. We propose a system that is better suited to the increasing complexities of combinations of genes involved in both race-specific and race-nonspecific recognition by the host, while at the same time updating the name of scab resistance loci (Rvik) and QTL loci (Qvik) to international standards. For the race-specific interactions, the basic premise is that each Rvik-AvrRvik and Qvik-AvrQvik relationship should be represented by a differential host (k), abbreviated to h(k), carrying only the specific Rvik or (major) Qvik resistance allele and an isolate of the pathogen having lost only the complementary allele at the AvrRvik or AvrQvik locus, race (k), with k representing the number of the specific interaction. Races lacking more than one avirulence gene at different loci will be identified as race (k,l,m,...) and apple hosts carrying multiple scab resistance genes as host (k,l,m,...). The proposed system has some continuity with the current system, but should simplify the presentation and interpretation of studies on avirulence alleles in V. inaequalis at the population level. Gene-for-gene relationships reported to date for this pathosystem are reviewed, some inconsistencies clarified, and several new interactions added. The gene-for-gene relationships of European isolates collected in the last decade have been studied in order to establish a new set of reference isolates that represent various V.inaequalis races.

International audience; Few years ago, apricot fruits characterized by a deep red-purple supra-colour covering nearly the whole surface of the apricot fruit were found in the apricot germplasm, Being introduced in breeding programmes, preliminary selections were obtained and evaluated on their horticultural potential. Their interest for the consumers and their post-harvest main characteristics were investigated. While for the consumers the distinctiveness between these fruits and the conventional apricots was cleal, part of the interviewees was attracted by the innovation, while another part was not concerned. However, special attention has to be paid to the harvest because the intense red-colour masks the green ground colour of the skin. In addition, some of the accessions issued from this germplasm are characterized by a rather fast post-harvest evolution. Thus, in order to protect the consumers and to sell the best fruits as possible, it has been proposed to develop all the apricot series under the same trade mark 'Rubisco'® and under a technical agreement proposed to all the growers. So far, three cultivars have been named: 'Ravicille', 'Ravilong' and 'Ravival' with different dates of ripening.

UMR DAP équipe AFEF;UMR DAP équipe AFEF;; Orchard planting systems are often associated with tree shape management which has direct and practical implications on training and pruning strategies. The objective of horticultural practices is to reach the required height and shape as fast as possible and maintain the tree framework in time and space. Scientific studies consider the individual crown shape and the spatial organization of trees within the orchard, which encompass tree height, planting distances, alley width and/or the leaf area index (LAI). Therefore, eco-physiological studies are mostly dedicated to the optimisation of orchard performances, highlighting the importance of light interception and distribution. At orchard level, the individual tree is often considered as a black box, and the turbid medium analogy hypothesized, i.e., tree crowns are filled with a uniform leaf area density and isolines of canopy light distribution are computed. An incremental improvement in the understanding of tree growth and fruiting strategies has been developed in the last three decades. Minimal pruning concepts have been proposed to fruit growers, limiting undesired vegetative reactions and taking advantage of the genetic variability of architecture. Applications of these concepts lead to early and more regular yield, and favour the homogeneity of fruit quality. Recent studies also showed that interactions exist between components of tree architecture, namely branching density and shoot growth dynamics, and development of orchard pests and diseases. Paralleling the better understanding of tree architecture, dramatic improvements of ecophysiological studies have been performed now including an explicit description of plant geometry. Using computer-generated three dimensional representations of digitised trees light interception and distribution can now be accurately modelled at tree and orchard scales. These approaches are therefore, capable of taking branch organisation into account and this can in turn open new hypotheses related to pest and disease occurrence. Emerging concepts in fruit tree manipulation, and their impacts on architecture and eco-physiology, undoubtedly open new avenues in orchard management with the objectives to meet horticultural sustainability, i.e., optimising labour efficiency and fertilizer and water use, and demanding less pesticide

International audience; The effects of cultivar susceptibility on the development of scab caused by Venturia inaequalis were observed in two experimental orchards where no fungicide protection was used against scab over a 5-year period. The weather during a 4-year period was conducive to apple scab development, and the results obtained demonstrate the advantages of using low-susceptibility cultivars to limit the development of apple scab epidemics on leaves as well as on fruits. Whereas 95.2–100% of the fruits of susceptible cultivars had apple scab at harvest, low-susceptibility cultivars were relatively less scabbed with only 3.1–46.5% of scabbed fruits. During years with low scab stress, it was very interesting to observe the almost total absence of the disease on the low-susceptibility cultivar, Reine des Reinettes, whereas on the susceptible cultivar, Gala, 40% of leaves and 22% of fruits were scabbed at harvest. These results confirm the interest of partial resistance for scab management in orchards. It is possible to take the level of susceptibility of cultivars into consideration within the framework of integrated fungicide protection against apple scab.

International audience; To limit peach brown rot incidence in 4-year-old late maturing peach trees, cultivar ‘Nectaross’, four combinations of irrigation and pruning treatments were assessed: conventional (Conv) irrigation (I) and pruning (P) (ConvI+ConvP); modified (Mod) irrigation and conventional pruning (ModI+ConvP); conventional irrigation and modified pruning (ConvI+ModP); and modified irrigation and pruning (ModI+ModP). Modified irrigation and pruning involved water deprivation and manual pruning, respectively. In 3 successive years, in the conditions of the Middle Rhone Valley in France, the lowest brown rot incidences were detected under (ModI+ModP) and the highest under (ConvI+ConvP), whereas brown rot incidences under (ModI+ConvP) and (ConvI+ModP) were intermediate. The lower brown rot incidences under modified treatments occurred before fruit maturity and were maintained until post-harvest storage. They suggest that appropriate cultural practices, water deprivation and manual pruning possibly decrease peach disease sensitivity, and this could result in reducing use of pesticide sprays against brown rot in orchards. Moreover, water deprivation and manual pruning tended to enhance peach taste quality—measured as a decrease of fruit firmness, and increase of total soluble solids—compared with conventional irrigation and pruning, but the average fruit weight decreased under the modified treatments. Nevertheless, because of the increase in marketable first-class fruit as a result of water deprivation and in fruit yield as a result of manual pruning, the relative profitability of fruit production tended to be higher under the modified treatments than under conventional conditions.

International audience; Among fruit species, apricot (Prunus armeniaca L.) is characterized by a large increase in the number of registered and/or granted cultivars over the last decades, and by an effective interest at the European level. At the same time, an evolution concerning fruit quality attributes was observed globally among registered cultivars. In order to characterize this tendency, 172 cultivars in collection were observed. Representative fruit samples have been collected and their quality attributes such as fruit weight, firmness, colour, soluble solids content, and titratable acidity were considered. The impacts of genetic and geographic origin factors were evaluated. A significant increase in fruit firmness and colour, as well as a decrease in fruit acidity, was observed. No evolution on sugar content was noticed.

International audience; Ascospores of Venturia inaequalis produced on scabbed leaves in the leaf litter are the main source of primary inoculum, causing infections in apple orchards. The purpose of this 2-year experiment, carried out in a commercial organic orchard, was to assess the effect of combining leaf sweeping from the alleys with leaf ploughing in within the row on scab inoculum and development. In 2003, scab severity was monitored at different distances from the unremoved leaf areas to estimate ascospore spreading. Scab incidence and severity were low in 2003 and high in 2004. At fruit harvest, both years, the leaf litter removal method reduced fruit scab incidence by 82.5% and 54.6% respectively, and fruit scab severity by 74.0% and 67.7%, respectively. Measures of scab lesion gradient indicated that ascospore spreading was not important beyond a 20 m distance from the source. The number of trapped ascospores observed in 2004 in the leaf removal treatment was reduced by 95%. Results from this 2-year experiment showed that leaf litter management by leaf removal allowed a reduction in apple scab inoculum and development and demonstrated the benefit of a complete removal of the leaf litter, when combining leaf sweeping from the alleys with leaf ploughing in within the row.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; The major resistance gene Pl-2 in apple has recently been shown to be overcome by a virulent population of powdery mildew, Podosphaera leucotricha, in genotypes of the fourth generation after introgression of Pl-2 from crab apple, Malus zumi. Tests of pathogenicity in controlled conditions and observations in an orchard showed that the initial progenitor of Pl-2, MAL 68/1, was overcome by a virulent inoculum. As a consequence, all selections derived from MAL 68/1 may lose their resistance to powdery mildew, if Pl-2 is used alone. Sources of resistance other than Pl-2 remained efficient to the virulent population: M. hupehensis, M. mandshurica, M. robusta, M. sargentii, M. sieboldii, D12, Mildew Immune Selection and 'White Angel'. The combination of Pl-2 with quantitative resistance genes resulted in a high level of resistance

Data obtained in 2005 from thinning experiments with ‘Ariane’ and ‘Pitchounette’ apples ( Malus × domestica L. Borkh.) were used to estimate tree mean fruit diameter (MD), weight (MW) and proportion of red overcolour (MC) using random samples. Twenty fruit per tree were taken from the boxes containing the fruit harvested at each picking. To avoid taking only fruit in the upper layers of the boxes, fruit from each tree were spread out on a table beforehand. The estimated values were compared with the true MD, MW or MC calculated from each picking and from the entire crop. Statistical techniques were used to assess agreement between the values obtained with estimation methods and the true values. Estimates obtained from a sample averaging ∼15–20% of total crop may range from 2 to 3% of the true mean diameter, and from 6.0 to 8.5% of the true mean weight. Estimates for MC obtained from the same samples may range from 10 to 25% of the true mean overcolour. The error margin associated with estimating fruit diameter and weight from the sampling method employed in this study seems to be small enough to consider it reasonably adequate to detect treatment differences that would be considered biologically or economically significant. Blind sampling and colour determination through image analysis are suggested as a means to obtain unbiased and objective data for fruit colour determinations.

SummaryCentrifugal training, based on the extinction procedure, is an innovative type of apple tree training recently used in French apple orchards. A thinning cut of fruiting spurs along the trunk and on the proximal and underside parts of the fruiting branches modifies the within-tree leaf density and light environment, which is likely to affect the development of some apple pests and pathogens. In this study, development of the most serious foliar pests (aphids, mites) and disease (apple scab) was assessed over 3 years in an organic apple orchard with two training systems: the centrifugal training (CT) system, and the Original Solaxe (OS) system, using a bent axis with no removal of fruiting spurs, as a control. Infestation levels were significantly lower in 2002 and 2004 in the CT system than in the OS system for the most prevalent pest, the rosy apple aphid, Dysaphis plantaginea and, in 2003, for the red spider mite, Panonychus ulmi. Infestation by the green apple aphid, Aphis pomi, was higher in Jun...

International audience; Fruit elaboration in orchards and post-harvest evolution are amongst the key factors to be kept under control in order to ensure fruit quality for the consumers. Due to the large variability already described in apricot ethylene production rate, we have focused on the comparison of contrasting apricot cultivars. For four apricot varieties (‘Moniqui’, ‘Goldrich’, ‘Bergeron’ and ‘A3759’), post-harvest storage at 23°C has been compared with fruit ripening on the tree, for three main traits: ethylene production, fruit firmness and colour changes. An earlier and higher ethylene production rate, associated with a faster loss of firmness, was observed post-harvest, in comparison with the fruit evolution on the tree. Colour changes also have been noticed. Differences amongst cultivars have been highlighted clearly.

International audience