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Drought stress significantly threatens crop productivity worldwide, requiring a comprehensive understanding of plant adaptations to alleviate its adverse effects. Sunflower, as an important source of edible oil, is greatly affected by drought in different developmental stages. This review investigates the morphological aspects and phenological adaptations of sunflower under drought conditions. Through a detailed description of morphological and phenological changes in sunflower, induced by drought, we aim to unravel the plant's strategies for coping with water scarcity. In addition, the study describes genetic background of drought tolerance in sunflower, as well as insight about valuable genetic resources. Finally, we have described drought mitigation mechanisms known in sunflower, through morpho-physiological adaptations and agricultural practices which can alleviate the effect of drought. As a future strategy this research emphasizes the importance of genetic diversity in cultivating drought-resilient sunflower, using modern breeding techniques through genomic selection and omic's technologies as a promising strategy in the face of escalating water limitations and development of drought tolerant and tenacious sunflower. [ABSTRACT FROM AUTHOR]

Sunflower co-products (i.e., stalks and heads) were recently used to create a value chain of sunflower biomass. On the one hand, bioactive ingredients extracted through twin-screw extrusion can be valorized as ecologically friendly agricultural products. On the other hand, in this study, the remaining solid, i.e., the extrudate, was used for obtaining bio-based materials, generating economical value with low environmental footprint. It is processable into cohesive boards through hot pressing. According to NF EN 312, optimal board (37 MPa flexural strength, and 33% thickness swelling) containing 9.1% (w/w) sunflower proteins as binder can be used as a type P2 board, i.e., for interior fittings (including furniture) in dry environments. For P3 and P4 types, a thickness swelling lower than 20% and 21%, respectively, will be required. The extrudate can be also separated into long fibers and fines. Long fibers can be compression molded into low-density insulation blocks (49 mW/m K thermal conductivity). Fines can be used as a filler for reinforcing (bio)plastics, e.g., polypropylene and poly (lactic acid). These bio composites could be injected into pots or tutors for plants, or even extruded into window openings or exterior decking. [ABSTRACT FROM AUTHOR]

The first web conference on sunflower–pollinator interactions gathered the international community around a major topic for sunflower productivity and ecosystemic biodiversity. Insect-mediated pollination is important for increasing sunflower seed yield, but is dependent on environmental factors. Climate change can impact sunflower-pollinator interactions by influencing both plant and pollinator behavior. Natural or artificially elevated ambient temperatures appear to accelerate floret development and advance the timing of pollen presentation to coincide with pollinator activities. Drought showed no major effect on morphological traits such anther or corolla length, but dramatically reduced nectar and pollen productions. Flavonol-glycoside conjugates lower head transpiration thereby mitigating deleterious effects of abiotic stresses. Wild pollinators show fine scale preferences among sunflower varieties, likely due to the different resource focus of wild and managed honeybees. Agricultural practices such as planting flower strips to provide nesting sites for wild pollinators, or supplementing crop plots with hives, can have a positive effect on insect-mediated pollination efficiency and ensure optimal yields. All together, recent results on sunflower–pollinator interactions pave the way to develop varieties and corresponding cropping systems more favorable to pollinator biodiversity while maintaining high yields in the context of climate change. [ABSTRACT FROM AUTHOR]

The development of organic agriculture in France was steady since 2010 but became stronger since 2014. Like other crops, the cultivated areas of organic soybean and sunflower doubled from 2014 to 2018. With a view to better characterize cultural practices in organic production, Terres Inovia and ITAB (in collaboration with Agence Bio) conducted in 2016 and 2017 a national farmers' survey. These surveys reveal that sunflower was mainly cultivated over the same types of soil than in conventional production but were integrated in more diversified rotations. The main differences between organic and conventional systems concern sowing date and weed control. Organic sunflower was sown very lately compared to conventional one, which impacted the yield severely. Weed were controlled through ploughing, mechanical weeding and crop rotation and weed control was judged as satisfying by a major part of producers. Concerning soybean, a great difference is the use of irrigation which is almost systematic in conventional but concerned only 50% of cultivated area in organic production. Contrary to sunflower, soybean is integrated in short crop rotation, particularly when it was irrigated. This demonstrated the high profitability of soybean in organic systems. Like for sunflower, weed control done through ploughing, mechanical weeding, and crop rotation and weed control was also judged satisfying; nevertheless, criteria on harvest impurities are more severe and to respect them, organic farmers also use hand weeding in complement. These surveys will be reconducted over the years to be able to follow the changes of cultural practices over the years. [ABSTRACT FROM AUTHOR]

Macrophomina phaseolina is a polyphagous phytopathogenic fungus that causes serious yield losses in economically important crop plants. The most appropriate control measure for this fungus is the utilization of resistance sources. To achieve this a fast and reliable screening method, in addition to a characterized pathogen population, is a prerequisite to accelerate breeding programmes. The aim of this study was to develop an efficient inoculation method for soybean and sunflower seedlings and to test the effect of inoculum maturity on disease development under controlled environmental conditions. Three inoculation methods, stem-tape, cut-stem and toothpick, and two inoculum types, hyphal and microsclerotial, were tested on sunflower and soybean seedlings. The fastest disease development on sunflower was obtained with the cut-stem and stem-tape inoculation methods using hyphal inoculum, and both methods had high repeatability. The cut-stem method, however, is not applicable for germplasm screening studies due to the predisposition of sunflower seedlings to pathogen attack. Application of the stem-tape inoculation method was useful for a variety of host reaction studies and for rapid germplasm screening. In soybean, the cut-stem inoculation method yielded consistent results in pathogenicity and variety reaction studies, but the stem-tape and toothpick inoculation methods had poor repeatability and long incubation periods, respectively. The cut-stem method in soybean and the stem-tape method in sunflower appear to be the most appropriate for pathogenicity and rapid germplasm screening studies with M. phaseolina under controlled conditions. [ABSTRACT FROM AUTHOR]

Twenty-one hybrids of sunflower were produced by crossing 7 introduced cytoplasmic male sterile lines (CMS-lines) with 3 restorer lines (RF-lines) using line x tester mating design. The twenty-one hybrids, three restorers, seven maintainer lines (B-lines) were evaluated. The experiment was conducted in a randomized complete block design of three replications. Mean squares due to genotypes, parents (P), crosses (C), lines (L), testers (T), P vs. C, for stearic acid and line x tester for palmitic acid. The inbred lines and their F1 hybrids differed significantly in their mean values of the traits under study. The variances due to specific combining ability (SCA) were higher than general combining ability (GCA) variances for all the studied traits, showing non-additive type of gene action controlling the traits. Non-additive type of gene action can be utilized for varietal improvement through heterosis breeding. Heterosis values for seed yield plant-1 were positive and highly significant relative to both the parental mean (17.68-72.38%) and the better parent (-2.86-56.842%). Significantly and negative heterosis was recorded in the case of linoleic acid relative to the parental mean (-81.24 to-38.02%) and better parent (-66.24-22.87%). With oleic acid, the heterotic effect ranged from 14.18 to 39.59% (parental mean) and from 15.06 to 38.72% (better parent). Therefore, these results are valuable for the improvement of quantitative as well as qualitative traits in sunflower breeding material to fulfill the edible oil requirements. [ABSTRACT FROM AUTHOR]

Bird damage to sunflowers (Helianthus annuus) degrades the profitability of this crop and calls into question its place in rotations. Our international literature review shows that sunflower is one of the crops most vulnerable to bird attacks. However, these predatory pests are not specialized: if the sunflower is affected in one region, then the other crops sharing the same cycle could also be affected to varying degrees. All production areas are affected by flowerhead damage at maturity. Damage at emergence has recently become more visible in France, Italy and Switzerland, probably as a result of global changes and evolving farming practices. Birds are highly mobile pests with complex behaviour. The problem needs to be tackled in a hierarchical framework that takes into account field, landscape, and regional scales, along with processes at different timescales from rapid field selection to long term demographic trends. Moreover, the distribution of damage is asymmetrical: few fields are affected, but with a high severity. At this time, there is no single effective method for preventing damage, and coordination at the landscape scale should be initiated to find potential solutions. Finally, there is a gap between theoretical and applied knowledge, even though initiatives in North America have helped to move research forward. These difficulties imply an integrated approach combining partially effective methods, the association of several stakeholders, and the coordination of several policies (agricultural, environmental, and recreational hunting or wildlife management). Additionally, data collection appears essential to acquire knowledge about economic damage and efficacy of control programmes. Digital technology can be useful for such purposes. Finally, this review advocates international networking to consolidate a research community on this topic and on the wider issue of bird damage to crops. [ABSTRACT FROM AUTHOR]

The aims of the present study were to assess the phenotypic diversity among 221 sunflower accessions of INTA Pergamino Sunflower Breeding Program, to obtain discriminant functions that allow the classification of new accessions in similar groups and to evaluate the relationship between genetic distance pairwise accessions and hybrid performance for grain yield and oil content. We used 19 quantitative descriptors to evaluate phenotypic and morphological variability. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used to evaluate simultaneously all the variables and to describe phenotypic variation patterns of the germplasm. The distribution of germplasm in the dendrogram did not follow a clear pattern with regard to the predefined groups. This study revealed the variability observed among the lines that form the INTA Pergamino breeding program despite the highly selective forces applied to obtain inbred lines that produce superior hybrids for the Argentinean sunflower area. This work demonstrates the need for more in-depth study of genetic variability to be used as a predictor of heterosis in sunflower. [ABSTRACT FROM AUTHOR]

Downy mildew is one of the most important diseases of sunflower crop around the world caused by Plasmopara halstedii (Farl.) Berl.et de Toni. The aim of our study was to evaluate the horizontal resistance of elite and prospective lines to downy mildew in field conditions. Experiments were conducted at All-Russia Research Institute of Oil Crops (VNIIMK) in 2016–2020. Released and prospective sunflower lines bred at VNIIMK were studied, divided into four groups on the base of their race-specific resistance in laboratory tests. Experimental design was randomized blocks with two replications. Evaluation was made by recording all the recognizable symptoms of downy mildew from emergence till flowering. The results obtained allowed us to identify the lines with the highest race non-specific resistance to downy mildew: VK 678 (5.3%), VK 653 (7.3%), VA 760 (3.3%), VA 93 (2.0%) and VK 732 (6.3%). The final aim is the development of sunflower hybrids with the most durable resistance to downy mildew, combining one parental line with the major gene (Pl15) most effective for the specific location and the second parental line with a high level of horizontal resistance to downy mildew. [ABSTRACT FROM AUTHOR]

The sunflower crop provides an important honey flow for beekeepers. In France, beekeepers observed a decrease in honey yield from this crop these past years compared to the 1980s-1990s. They suspect the new cultivars to be less productive in nectar compared to the older ones, but no data is available to support this, and it is known that climate conditions have a strong impact on nectar secretion. This study aimed to explore the effect of abiotic environmental conditions on nectar secretion in sunflower, as well the range of variation of this secretion in a sample of current cultivars. Thirty-four current sunflower hybrid cultivars were sampled in test plots for their nectar secretion under varying conditions of temperature, air humidity and soil moisture. Air humidity controlled the sugar concentration of nectar, and thus its volume. To study nectar secretion independently from this effect, analyses subsequently focused on nectar sugar mass per floret. The nectar sugar mass increased with temperature up to an optimum of 32 °C, while the variation range of soil water tension was not sufficient to detect an effect on nectar sugar mass. This varied by up to 100% among the 34 cultivars (from 101 to 216 mg sugar per staminate floret in average), with a similar range to those reported in the literature for older cultivars. Likewise, oleic cultivars, a new type introduced since the early 2000s, were found to secrete the same amounts of nectar as linoleic cultivars, an older conventional type. The more self-fertile cultivars also showed no reduction in nectar secretion. Finally, we tested the method that measures the nectar gross secretion rate in one hybrid, and we observed that this hybrid secreted in average 28 mg sugar per hour per staminate floret. The potential benefits of this method were discussed. [ABSTRACT FROM AUTHOR]

This article describes how RNA expression data of 173 genes were produced on 384 sunflower hybrids grown in field conditions. Sunflower hybrids were selected to represent genetic diversity within cultivated sunflower. The RNA was extracted from mature leaves at one time seven days after anthesis. These data allow to differentiate the different genotype behaviours and constitute a valuable resource to the community to study the adaptation of crops to field conditions and the molecular basis of heterosis. It is available on data.inra.fr repository. [ABSTRACT FROM AUTHOR]

The International Sunflower Conference takes place every four years under the auspices of the ISA, International Sunflower Association. Before the 20th Conference in June 2020, a review of the proceedings of the Edirne conference, in June 2016, offers a vision of the crop and research dynamics in the world, as well as international cooperation programmes in progress or to be developed in the period 2016-2020. They are essential for the future of this crop for which demands tend to diversify. Sustained efforts have led to significant progress in genomics. The challenges posed by pests and by climatic constraints remain significant. The interest in gathering knowledge on crop models incorporating varietal parameters appears clearly, both to establish long-term adaptation strategies and to make better use of current resources. [ABSTRACT FROM AUTHOR]

In order to make more efficient plant breeding and gain in competitiveness, the sector of oilprotein crops decided to intensify agronomic research on sunflower crop. The "Sunflower" Joint Technological Unit (UnitéMixte Technologique(UMT) "Tournesol", in French) was launched in the Toulouse area in 2006, associating closely INRAandTerres Inovia. First focused on improving oil production through an agronomic approach, theUMTwas renewed in 2011 with a broader partnership and amore assertive orientation towards the development of decision-making tools. The objective of this paper is to highlight the relevance and productivity of this user-oriented research facility. The main results relate to (i) the co-construction of a simulation model (SUNFLO) that can be parameterized and manipulated by Terres Inovia engineers, (ii) the joint exploration of supra-field scales and newmethods for agronomic diagnosis and yield forecasting based on remote sensing, (iii) the tuning and dissemination of operational decision rules, (iv) the production of essential knowledge on emergent and/or damaging fungal diseases, as well as on complex interactions between genotype, environment and crop management. After a concluding symposium in 2016, new requests for sunflower research were formulated by the participants. They also advocated for a diversification of crops to consider in order to better meet the needs of the whole oil-protein sector. [ABSTRACT FROM AUTHOR]

Modern breeding of sunflower (Helianthus annuus L.), which started 100 years ago, increased the number and the diversity of cultivated forms. In addition, for more than 50 years, wild sunflower and other Helianthus species have been collected in North America where they all originated. Collections of both cultivated and wild forms are maintained in gene banks in many countries where sunflower is an important crop, with some specificity according to the availability of germplasm and to local research and breeding programmes. Cultivated material includes land races, open pollinated varieties, synthetics and inbred lines. The majority of wild accessions are ecotypes of wild Helianthus annuus, but also 52 other species of Helianthus and a few related genera. The activities of three gene banks, in USA, France and Serbia, are described in detail, supplemented by data from seven other countries. Past and future uses of the genetic resources for environmental adaptation and breeding are discussed in relation to genomic and improved phenotypic knowledge of the cultivated and wild accessions available in the gene banks. [ABSTRACT FROM AUTHOR]

Leaf blight of sunflower caused by Alternaria spp. occurs frequently in the Beijing municipality of China. A total of 482 Alternaria isolates were obtained from sunflower leaves with typical dark fleck symptoms sampled from 13 different districts in the Beijing municipality in 2014. Morphological observations and sequence analyses of the rDNA-ITS region and the histone 3 gene revealed that two Alternaria species, A. tenuissima (86.5% frequency) and A. alternata (13.5% frequency), were associated with the disease. Four isolates of A. tenuissima and six of A. alternata were pathogenic to sunflower leaves with disease incidence and disease index ranging from 50−100% and 16.7–33%, respectively. This is the first comprehensive examination of the involvement of Alternaria species in leaf blight of sunflower of Beijing, China. [ABSTRACT FROM AUTHOR]

La pollinisation entomophile du tournesol est souvent mentionnée comme un facteur contribuant au rendement et à la qualité de cette culture. Alors que les rendements stagnent depuis une trentaine d'années en France, l'amélioration de la pollinisation des tournesols de consommation constitue une piste pour les relancer en conditions agricoles. Notre étude visait à évaluer l'impact d'un front d'insectes pollinisateurs (colonies d'abeilles domestiques installées dans une bande fleurie disposée sur une bordure de parcelles agricoles longue de plus de 550 m de long). Cet impact a été mesuré à différentes distances de ce front d'insectes pollinisateurs sur la fréquentation des capitules par les insectes floricoles, la charge en pollen des stigmates, le rendement et la teneur en huile des graines. Nous avons bien observé un gradient négatif d'activité des abeilles domestiques en fonction de l'éloignement au front de colonies et aussi une diminution du rendement et de la teneur en huile chez le tournesol. Nous présentons la méthodologie originale utilisée ainsi que les premiers résultats obtenus.

Sunflower is one of the most important oilseed crops in the world, since its grains have high oil content (38% to 50%), primarily used for the production of high quality oil. The production of sunflower increases the supply of protein meal for animal feeding, which enables the increase of protein production, more specifically meat, eggs and milk. Grain production systems in Brazil have peculiarities, since two to three different crops are grown in a special arrangement, in the same area and year. Notwithstanding the small cultivated area in Brazil of 62.3 thousand hectares, sunflower is used in succession or rotation with other grain crops such as soybean or maize, showing an enormous potential for expansion and can be cultivated from latitudes 33°S to 5°N, especially in the Brazilian Cerrado biome. Sunflower cultivation in succession to soybean as a second summer crop can also reduce environmental impacts because of the more efficient usage of production factors, such as land and sharing of agricultural inputs, machinery, infrastructure and workforce. The success of establishing the sunflower is associated with the adequate management of soil fertility, use of cultivars adapted to different environments, plant arrangement, seed quality and adequate phytosanitary management, among other factors. It also needs strategic actions, planning and, long-term research and technology diffusion. [ABSTRACT FROM AUTHOR]

Sunflower pollination has been a subject of research for more than 40 years at the Institute of Field and Vegetable Crops in Novi Sad, Serbia. Since the first experiments in 1970s, the importance of climatic conditions was acknowledged and analyzed as a key factor for the performance of plants and pollinators. Climatic conditions, disease and pest problems changed significantly during this period, but sunflower production technology and breeding also advanced making seed production more stable. Nonetheless, the quality of agronomic practices still varies which also reflects on the plant and pollinator performance. Sunflower breeding led to improved germplasm which still maintains high degree of variability for nectar content and pollinator attractivity. Pollinators are essential in crosses involving cytoplasmic male sterile lines, but are also beneficial in hybrid sunflower seed production. Pollinator attractivity is thus an important trait for both breeders and producers and worth to be considered as a quality trait in sunflower breeding programs. [ABSTRACT FROM AUTHOR]

Sunflower ( Helianthus annuus L.) can often display seed dormancy, which causes a delay for immediate sowing. The final degree of 'whole seed' dormancy is determined by the contributions of the tissues that comprise it, such as, embryo, seed coat, and (or) pericarp. The sunflower dormancy can be reduced during after-ripening and by removing seed constraints. Our objective was to study how the conditions of storage and removal of the pericarp affect the level of dormancy in line A-3. Also we provide insight on the basis of the morphological characteristics of A-3 pericarp-imposed dormancy. A germination test was conducted on dry cypselas with and without pericarp, at 30 and 70 days after harvest. For histological analysis, permanent slides of pericarp cross-sections were obtained. The germination percentage showed significant differences between cypselas with intact pericarp (30 days after harvest = 26%; 70 days after harvest = 77%), and cypselas without pericarp (30 days after harvest = 65%; 70 days after harvest = 96%). This indicates that the pericarp plays an important role in regulating physical dormancy in the seed of sunflower line A-3, and that its relative contribution to the dormancy level is modified during after-ripening. [ABSTRACT FROM AUTHOR]

La graine de tournesol est un aliment avec un fort potentiel sensibilisant mais finalement peu d'allergies confirmées. Les modes de sensibilisation sont multiples, respiratoires, digestifs et cutanés. De nombreuses manifestations cliniques ont été décrites, les profils des patients sont également très variés. Des réactions à l'huile de tournesol sont possibles mais exceptionnelles. Des prick-tests avec l'aliment natif et la recherche d'IgE spécifiques confirmeront le diagnostic. La recherche d'allergènes moléculaires a permis d'identifier notamment une LTP et des albumines 2S. Nous rapportons une série de cas déclarés au Réseau d'Allergo-Vigilance® et faisons une revue de la littérature sur le sujet. Sunflower seed is a food with a high sensitising potential but few allergies have been confirmed. Sensitization modes are multiple, respiratory, digestive and cutaneous. Numerous clinical manifestations have been described, and patient profiles are also very various. Reactions to sunflower oil are possible but very rare. Prick tests with the native food and the search for specific IgE antibodies will confirm the diagnosis. The search for molecular allergens has allowed the identification of LTP and 2S albumin. We report a series of cases declared to the Allergy-Vigilance Network®, and review the literature on the subject. [ABSTRACT FROM AUTHOR]

Sunflower ( Helianthus annuus L.) is used as 'seed snacks', so called 'pipas', in the Mediterranean countries which may offer an interesting opportunity for agricultural diversification of this crop. The morpho-phenological variability already demonstrated in the Tunisian local populations can be a basis for the creation of new varieties well adapted to climate and soil conditions in that region. The molecular characterization of 59 accessions and reference lines generated 194 alleles from 30 SSR loci (3-10 alleles per locus) and 54 haplotypes, built from 117 SNP detected by NGS sequencing of 7 genes (4-16 haplotypes per gene). These data highlight some uniqueness of the Tunisian material compared to 7 control lines but a low genetic dispersion between accessions. However, a core collection of 8 populations, capturing 88 % of the Tunisian genetic diversity, could be proposed for a future sunflower breeding program. [ABSTRACT FROM AUTHOR]

Sunflower seed quality, in particular the characteristics of hullability and protein content, has a significant impact on the protein content of the resulting meal. Seeds dehulled before crushing produce a meal with a protein content of approximately 36%; without dehulling, the protein content is typically in the range of 27-29%. This study seeks to assess the effect of sunflower variety on hullability and protein content. Genetic effects were studied by means of seed samples obtained from a network of variety evaluation trials undertaken across the production area in France for sunflowers. For both characteristics, significant differences between cultivars were observed; as a consequence, the potential protein content of their dehulled meals also ranged widely (34-44%). Genetic selection, which provides substantial improvements in both oil content and fatty acid composition, should therefore be expected to enhance the quality of sunflower meal. [ABSTRACT FROM AUTHOR]

In France, sunflower honey production has decreased since the nineties and professional beekeepers report important honey yield variability between years and locations. Consequently, melliferous potential of current sunflower cultivars is questioned as it is not part of traits held in breeding programs. To investigate this question, a 3-years study was conducted on two sites and attractiveness for honeybees of 13 current sunflower cultivars was assessed under natural conditions. The number of honeybee visits per plant was recorded daily during blooming period on cultivars randomly distributed on experimental plots. Sunflower genetic was a major factor influencing honeybee attendance on plots and discrepancy between most and least visited cultivars reached a factor of 3. Cultivars relative attractiveness was consistent between years and sites. Potential link between sunflower attractiveness for honeybees and its melliferous characteristics is discussed. If confirmed, farmers' choice concerning cultivars at a territory scale could contribute to enhance nectar resource for pollinators and to increase viability of apicultural activity. [ABSTRACT FROM AUTHOR]

Sunflower appears as a potentially highly competitive crop, thanks to the diversification of its market and the richness of its oil. However, seed oil concentration (OC) - a commercial criterion for crushing industry - is subjected to genotypic and environmental effects that make it sometimes hardly predictable. It is assumed that more understanding of oil physiology combined with the use of crop models should permit to improve prediction and management of grain quality for various end-users. Main effects of temperature, water, nitrogen, plant density and fungal diseases were reviewed in this paper. Current generic and specific crop models which simulate oil concentration were found to be empirical and to lack of proper evaluation processes. Recently two modeling approaches integrating ecophysiological knowledge were developed by Andrianasolo (2014, Statistical and dynamic modelling of sunflower (Helianthus annuus L.) grain composition as a function of agronomic and environmental factors, Ph.D. Thesis, INP Toulouse): (i) a statistical approach relating OC to a range of explanatory variables (potential OC, temperature, water and nitrogen stress indices, intercepted radiation, plant density) which resulted in prediction quality from 1.9 to 2.5 oil points depending on the nature of the models; (ii) a dynamic approach, based on "source-sink" relationships involving leaves, stems, receptacles (as sources) and hulls, proteins and oil (as sinks) and using priority rules for carbon and nitrogen allocation. The latter model reproduced dynamic patterns of all source and sink components faithfully, but tended to overestimate OC. A better description of photosynthesis and nitrogen uptake, as well as genotypic parameters is expected to improve its performance. [ABSTRACT FROM AUTHOR]

Sunflower broomrape (Orobanche cumana Wallr.) parasitization on sunflower was first observed at the end of the 19th century and has continued since then jeopardizing sunflower cultivation in many areas of Europe and Asia. A distinctive characteristic of the O. cumana-sunflower parasitic system is that it is mainly governed by a gene-for-gene interaction. This determines complete resistance in the host controlled by dominant alleles at a single locus, which facilitates the management of the resistance for hybrid seed production. But on the other hand avirulence in the parasite is also controlled by dominant alleles at a single gene. Monogenic, dominant resistance exerts a strong selection pressure on the parasite that maximizes the probability of overcoming resistance mechanisms in a short period of time. This has in fact resulted in a number of physiological races that periodically surpass all the available resistance sources. The spread of populations to new areas and the subsequent hybridization between populations is another mechanism creating genetic diversity in sunflower broomrape and allegedly recombination of avirulences genes. After more than one century of coexistence, genetic resistance to broomrape in sunflower has to be focused under an integrated approach that considers not only the characterization of resistance mechanisms in the host, but also the genetic and physiological bases of avirulence in the parasite. From the perspective of genetic resistance in sunflower, most important is not relying only on single dominant genes, but following instead pyramiding strategies. These should give priority to combining complementary mechanisms of resistance under both qualitative (vertical) and quantitative (horizontal) genetic control. These aspects are discussed in the paper. [ABSTRACT FROM AUTHOR]

Two lignocellulosic agricultural residues, sunflower stalks and rape straw, were investigated as potential low-cost, non-food substrates for the production of triacylglycerols by the oleaginous, lignocellulolytic bacteria Streptomyces lividans. Chemical analysis of each type of residue revealed similar cell wall compositions in the polysaccharides and lignins of the two feedstocks, with high lignin β-O-4 bond content compared to other angiosperms' lignin. Growing tests of Streptomyces lividans TK 24 were performed before and after sequential water and ethanol extraction by assessing bacterial fatty acid accumulation. All extracted and non-extracted samples were found to be substrates of the bacteria with fatty acid production ranging between 19% and 44% of the production obtained with arabinose as a reference substrate. The maximum conversion rate was obtained with the less lignified, non-extracted sample. This study suggests that lignocellulosic residues from oleaginous crops could be advantageously valorized by microbial bioconversion processes for the production of lipids of interest. [ABSTRACT FROM AUTHOR]

L’étude a été consacrée à l’évaluation des performances techniques d’esters méthyliques isomérisés dans des applications ciblées de l’industrie des peintures et vernis où les solvants à remplacer sont des composés organiques volatils en grandes proportions, ce sont : les lasures (55 à 65 %), les vernis (45 à 55 %), les peintures laquées (35 à 40 %), les peintures satinées (40 à 45 %) et les peintures anticorrosion (30 à 40 % de COV). Les esters méthyliques étudiés sont : -- les esters méthyliques de tournesol classique isomérisés cis-trans, -- les esters méthyliques de tournesol classique isomérisés trans-trans. Les résultats de cette étude ont démontré que les esters méthyliques conjugués de tournesol classique peuvent remplacer les solvants organiques volatils (white spirit par exemple) des peintures murales (brillantes et satinées) et des lasures. Ces esters jouent non seulement le rôle de solvant mais aussi celui d’un réactif de siccativation. En effet, ils participent à la formation du film de peinture ou de lasure au cours du séchage. En formulation de vernis et de lasures, les résultats montrent qu’il est possible d’incorporer des taux d’esters méthyliques de tournesol conjugués à hauteur de 10 %, ce qui permet de ramener le taux de COV de 550-650 g\\l à moins de 400 g\\l. En formulation de peintures laquées, la performance des esters méthyliques dépend non seulement du type de laque étudiée « brillante » ou « satinée » et surtout du système résine\\ETI (Esters de Tournesol Isomérisés). Les esters méthyliques conjugués peuvent être utilisés plus favorablement dans les laques brillantes, jusqu’à une concentration de 2,5 % en substitution des solvants hydrocarbonés habituels (white spirit D40 ou D60). Ils permettent dans ce cas d’augmenter sensiblement l’extrait sec, tout en restant conforme aux objectifs fixés par le CEPE pour les peintures (COV

Les enjeux de la génomique végétale sont immenses pour le secteur de la création variétale et concernent de multiples objectifs, allant de la réduction d’intrants à l’amélioration de la qualité des produits récoltés ou transformés. Une situation d’oligopole se met en place au niveau mondial avec quelques firmes provenant du secteur de la chimie, principalement aux États-Unis avec de très forts soutiens publics. En 1998, l’Inra, le CNRS, le Cirad, l’IRD pour le secteur public et Biogemma, Aventis Crop Ssciences et Bioplante pour le secteur privé s’engagent dans le programme Génoplante, acté, en février 1999, par le ministère de la Recherche, qui y apporte son soutien, pour une première période de cinq ans, afin de permettre à nos recherches, fondamentale et appliquée en biologie végétale, de rester compétitives. Le programme Génoplante comprend d’abord des programmes génériques : analyse fonctionnelle du génome d’Arabidopsis, génomique du riz, nouveaux outils d’analyse des génomes, bio-informatique, cibles importantes dans le génome des plantes cultivées. L’évaluation des projets soumis dans ce cadre est réalisée par des experts internationaux indépendants. Globalement, plus de 300 chercheurs sont impliqués dans ces projets. Il comprend aussi des programmes par espèces (blé, maïs, colza, tournesol, pois) ayant chacun une partie générique (cartographie physique, banques génomiques, etc.) et des projets concernant des caractères agronomiques, des stratégies de résistance aux maladies, ou des objectifs de caractérisation et d’amélioration de la qualité des produits.

L’Union européenne est un acteur important du marché international des oléagineux. Ses besoins en protéines et en huiles végétales sont extrêmement élevés. Bien que, entre 1980 et 1994, cette zone ait sensiblement augmenté ses surfaces en oléagineux, elle reste un producteur mondial modeste et doit importer de pays tiers l’essentiel de ses besoins en graines, tourteaux et huiles. L’Amérique du Nord et celle du Sud constituent ses principaux fournisseurs, de même que certains pays asiatiques comme la Malaisie ou l’Indonésie, mais les échanges à l’intérieur de l’UE et avec les PECOS se sont nettement développés. Le faible taux de couverture de l’Europe, particulièrement en tourteaux, rend cette zone très vulnérable aux aléas du marché mondial et aux décisions qui peuvent être prises à l’étranger et tout particulièrement aux États-Unis. Alors que la mise en place de l’Agenda 2000, caractérisée par un net recul des surface dès la première année d’application, pose de nouveaux problèmes de compétitivité à ces cultures dans un contexte de faibles prix mondiaux, le maintien de cette filière demeure un bien collectif pour les différents acteurs : consommateurs, agriculteurs, transformateurs et citoyens.

Molecular phylogenetic studies have contributed significantly to our understanding of the phylogenetic relationships of Helianthus, although several problems remain to be resolved. Molecular data have resolved problems with the circumscription of Helianthus. Its sister group is Phoebanthus, a narrowly distributed genus of two species from the state of Florida. The sister group to the Helianthus-Phoebanthus clade is a diverse set of taxa that occurs in Mexico and South America. These include species now classified as part of the paraphyletic Viguiera as well as such distinctive genera as Tithonia, Simsia, Pappobolus, Scalesia, Lagascea, and Alvordia. Incongruence between results based on chloroplast and nuclear-based data sets suggests that hybridization has been involved in the evolutionary history of this group. The nearest outgroup to the clade containing Helianthus is composed of members of Viguiera sect. Maculatae, which are trees and shrubs of Mexico. Other basally diverging groups in the subtribe Helianthinae to which Helianthus belongs are primarily woody members now classified in Viguiera from Mexico and nearby areas. Within Helianthus, divergence appears to be recent, based on an overall lack of divergence between species. The chloroplast-based tree suggests that Helianthus includes four phylogenetic lineages, whereas the nuclear ITS sequence data suggests that the perennial species are paraphyletic relative to the rest of the genus, with basally diverging branches consisting of species confined to the southeastern US. Because there is a lack of divergence among many groups of species, more variable markers will be required to resolve fully relationships within Helianthus.

In sunflower ( Helianthus annuus L.), there has been an intense genetic selection for achenes with agronomic value, such as greater mass, oil content, and disease resistance. However, the information regarding the anatomical events that control their growth and maturation is surprisingly scarce. The aim of the present work was to study sunflower male and female sporogenesis and gametogenesis, as well as cell division and enlargement and tissue differentiation in the ovary and the embryo, linking the timing of these events to two frequently used phenological scales and a thermal time scale. In addition, we propose an ontogenetic scale that integrates the results of the present work to that of previous studies on sunflower reproductive development. The unified scales presented here provide a framework for others to investigate the relationships uncovered in this study in different genetic backgrounds and under different growing conditions. [ABSTRACT FROM AUTHOR]

Le mildiou du tournesol, causé par l’oomycète Plasmopara halstedii, est une maladie potentiellement dévastatrice et économiquement importante. Du fait du risque de propagation de la maladie par les semences infectées et de l’observation croissante de l’apparition d’isolats résistants au métalaxyl, il est apparu nécessaire de mettre au point une méthode de détection du parasite dans les graines ou les tissus de la plante. Nous avons donc développé un test moléculaire pour le diagnostic de la présence du mildiou dans les semences. Plusieurs méthodes d’extraction ont été comparées pour améliorer le rendement et la qualité de l’ADN du parasite présent en faible quantité. Des échantillons de graines contaminées entières et décortiquées ont été analysés par PCR, avec des amorces spécifiques de Plasmopara halstedii. L’ADN de l’agent pathogène est toujours détecté, notamment dans les coques. Ces données sont importantes pour le développement d’un kit de diagnostic.

Un historique de l’utilisation des matières premières naturelles dans les savons et détergents suivi d’une présentation de la répartition des matières hydrophobes naturelles en fonction de leur origine. Quelques applications de tensioactifs provenant du colza et du tournesol sont décrites.

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The Compositae is one of the largest and most economically important families of flowering plants and includes a diverse array of food crops, horticultural crops, medicinals, and noxious weeds. Despite its size and economic importance, there is no reference genome sequence for the Compositae, which impedes research and improvement efforts. We report on progress toward sequencing the 3.5 Gb genome of cultivated sunflower (), the most important crop in the family. Our sequencing strategy combines whole-genome shotgun sequencing using the Solexa and 454 platforms with the generation of high-density genetic and physical maps that serve as scaffolds for the linear assembly of whole-genome shotgun sequences. The performance of this approach is enhanced by the construction of a sequence-based physical map, which provides unique sequence-based tags every 5-6 kb across the genome. Thus far, our physical map covers ∼85% of the sunflower genome, and we have generated ∼80× genome coverage with Solexa reads and 15.5× with 454 reads. Preliminary analyses indicated that ∼78% of the sunflower genome consists of repetitive sequences. Nonetheless, ∼76% of contigs >5 kb in size can be assigned to either the physical or genetic map or to both, suggesting that our approach is likely to deliver a highly accurate and contiguous reference genome for sunflower. [ABSTRACT FROM AUTHOR]

The soil-borne fungus Verticillium dahliae Kleb. causes a serious wilt disease in many economic crops worldwide, including sunflower. We investigated the role of V. dahliae's necrosis and ethylene-inducing proteins (VdNEP) in the interaction with sunflower. We inoculated two highly and two weakly aggressive V. dahliae isolates onto moderately resistant and susceptible sunflower hybrids. We also synthesized VdNEP protein in vitro and infiltrated it into sunflower control plants to compare its effects with those of the fungus. VdNEP induced wilting symptoms, i.e. chlorosis, necrosis and vascular discoloration but also triggered host defence responses, i.e. hypersensitive response in Nicotiana benthamiana leaves and sunflower cotyledons. It activated the production of reactive oxygen species and the accumulation of fluorescent compounds in sunflower leaves, as well as pathogenesis-related genes (Ha-PR-3 and Ha-PR-5), two defensin genes (Ha-PDF and Ha-CUA1) and those encoding Ha-ACO, Ha-CHOX, Ha-GST and Ha-SCO. The latter suggested that more than one signalling pathway may be involved in the V. dahliae-sunflower interaction. Two other genes (Ha-PAL and Ha-NML1), related to the salicylic acid pathway, were slightly downregulated by VdNEP, suggesting a possible involvement of VdNEP in affecting sunflower defences. The phenotypic changes induced by VdNEP indicate that this protein acts both as a defence elicitor and a pathogenicity factor. [ABSTRACT FROM AUTHOR]

Orobanche cumana Wallr., a root parasitic angiosperm, causes severe yield losses in Helianthus annuus L. (sunflower) in Europe. Until now, the only effective method of controlling this parasite has been the use of resistant sunflower genotypes. Broomrape resistance is, however, poorly understood even though previous studies have revealed several defence mechanisms. The study of a susceptible (2603) and a resistant (LR1) sunflower genotype in hydroponic co-culture showed that the degree of infection by broomrape is influenced by the concentration of nutrients in the growth medium. For the susceptible genotype, an increase in broomrape necrosis was observed when the nutrient concentration was increased. In the resistant genotype LR1, the rate of infection was reduced by increasing the concentration of mineral nutrients, measured as a decrease in broomrape attachments and a lack of underground stem development. When sunflowers were cultivated in full-strength medium, these findings correlated with a lower 14C incorporation in broomrape and a change in carbon allocation to host plant organs with a reinforced "shoot apex sink strength". Results demonstrated that in controlled conditions, the nutrient concentration directly affects sunflower resistance potential towards broomrape. [ABSTRACT FROM AUTHOR]

In the present work we report new tools for the characterization of the complete chromosome complement of sunflower (Helianthus annuus L.), using a bacterial artificial chromosome (BAC) clone containing repetitive sequences with similarity to retrotransposons and a homologous rDNA sequence isolated from the sunflower genome as probes for FISH. The rDNA signal was found in 3 pairs of chromosomes, coinciding with the location of satellites. The BAC clone containing highly represented retroelements hybridized with all the chromosome complement in FISH, and used together with the rDNA probe allowed the discrimination of all chromosome pairs of sunflower. Their distinctive distribution pattern suggests that these probes could be useful for karyotype characterization and for chromosome identification. The karyotype could be subdivided into 3 clear-cut groups of 12 metacentric pairs, 1 submetacentric pair, and 4 subtelocentric pairs, thus resolving previously described karyotype controversies. The use of BAC clones containing single sequences of specific markers and (or) genes associated with important agricultural traits represents an important tool for future locus-specific identification and physical mapping. [ABSTRACT FROM AUTHOR]

In this paper we report on the isolation and characterization, for the first time, of a complete 6511 bp retrotransposon of sunflower. Considering its protein domain order and sequence similarity to other copia elements of dicotyledons, this retrotransposon was assigned to the copia retrotransposon superfamily and named HACRE1 (Helianthus annuus copia-like retroelement 1). HACRE1 carries 5′ and 3′ long terminal repeats (LTRs) flanking an internal region of 4661 bp. The LTRs are identical in their sequence except for two deletions of 7 and 5 nucleotides in the 5′ LTR. Based on the sequence identity of the LTRs, HACRE1 was estimated to have inserted within the last ~84 000 years. The isolated sequence contains a complete open reading frame with only one complete reading frame. The absence of nonsense mutations agrees with the very high sequence identity between LTRs, confirming that HACRE1 insertion is recent. The haploid genome of sunflower (inbred line HCM) contains about 160 copies of HACRE1. This retrotransposon is expressed in leaflets from 7-day-old plantlets under different light conditions, probably in relation to the occurrence of many putative light-related regulatory cis-elements in the LTRs. However, sequenced cDNAs show less variability than HACRE1 genomic sequences, indicating that only a subset of this family is expressed under these conditions. [ABSTRACT FROM AUTHOR]

The article presents a study on the pathogenic changes in choosing low aggressive isolates of Verticillium dahliae after series of transitions in potato and sunflower plants. It states the determination of contaminant levels in Verticillium species prior to inoculation, and the selection of V. dahliae based on its weak aggression on both plants. Results of the study reveal an infection growth in potato cultivar while pathogenic variations were not observed in initial isolation after inoculation.

The purpose of this study was to identify genomic regions controlling seed protein content, kernel and hull weights, and seed density in water-stress conditions in sunflower (Helianthus annuus L.). The experiments consisted of a split-plot design (water treatment and recombinant inbred lines) with three blocks in two environments (greenhouse and field). High significant variation was observed between genotypes for all traits as well as for water treatment × genotype interaction. Several specific and nonspecific QTLs were detected for all traits under well-watered and water-stress conditions. Two SSR markers, ORS671_2 and HA2714, linked to protein content were identified that have no interaction with water treatments in greenhouse conditions. We also detected the E35M60_4 marker associated with kernel weight that had no interaction with water treatments. A specific QTL for protein content was detected with important phenotypic variance (17%) under water-stress conditions. Overlapping QTLs for protein content and seed density were identified in linkage group 15. This region probably has a peliotropic effect on protein content and seed density. QTLs for protein content colocated with grain weight traits were also identified. [ABSTRACT FROM AUTHOR]

The objectives of the present research were to determine the effects of water stress on seed-quality traits and to map QTLs controlling the studied traits under two different water treatments in a population of sunflower recombinant inbred lines (RILs). Two experiments were conducted in greenhouse and field conditions, each with well-watered and water-stressed treatments. The experiments consisted of a split-plot design (water treatment and RIL) with three blocks. Analyses of variance showed significant variation among genotypes, and a water treatment × genotype interaction was also observed for most of the traits. Two to 15 QTLs were found, depending on trait and growth conditions, and the percentage of phenotypic variance explained by the QTLs ranged from 5% to 31%. Several QTLs for oil content overlapped with QTLs for palmitic and stearic acid contents in all four conditions. An overlapping region on linkage group 3 (QTLs 2.OC.3.1 and 4.SA.3.1) was linked to an SSR marker (ORS657). A principal component analysis was performed on four fatty acid traits. Two principal components, P1 and P2, were used for QTL analysis. This method improved the ability to identify chromosomal regions affecting the fatty acids. We also detected the principal-component QTLs that did not overlap with the fatty acid QTLs. The results highlight genomic regions of interest in marker-based breeding programmes for increasing oil content in sunflower. Les objectifs de ce travail étaient de déterminer les effets d’un stress hydrique sur la qualité des graines et de cartographier des QTL contrôlant ces caractères sous deux régimes hydriques au sein d’une population de lignées recombinantes fixées (« RIL ») de tournesol. Deux expériences ont été réalisées dans des serres et au champ avec, dans chaque cas, un traitement sans et un autre avec stress hydrique. Un dispositif expérimental en tiroirs (« split-plot », régime hydrique et RIL) avec trois répétitions a été employé. L’analyse de variance a montré une variation significative parmi les génotypes ainsi qu’une interaction régime hydrique × génotype significative pour la plupart des caractères à l’étude. Entre 2 et 15 QTL ont été identifiés selon le caractère et les conditions de croissance. La part de la variance phénotypique expliquée par ces QTL variait entre 5 et 31 %. Plusieurs QTL ont été trouvés pour la teneur en huile, lesquels coïncidaient avec des QTL pour la teneur en acides palmitique et stéarique dans les quatre conditions. Une de ces régions de colocalisation de QTL sur le groupe de liaison 3 (2.OC.3.1 et 4.SA.3.1) était liée à un microsatellite (ORS657). Une analyse en composantes principales (« PCA ») a été réalisée sur quatre caractères relatifs aux acides gras. Deux composantes principales, P1 et P2, ont été employées lors d’une analyse QTL. Cette méthode a accru la capacité d’identifier des régions chromosomiques contrôlant les acides gras. Des QTL-PCA qui ne coïncidaient pas avec des QTL pour les acides gras ont également été détectés. L’ensemble des résultats met en lumière des régions génomiques pouvant servir en sélection assistée par marqueurs pour accroître la teneur en huile chez le tournesol. [ABSTRACT FROM AUTHOR]

The sunflower is one of the four most important oilseed crops in the world, and the nutritional quality of its edible oil ranks among the best vegetable oils in cultivation. Typically up to 90% of the fatty acids in conventional sunflower oil are unsaturated, namely oleic (C 18:1, 16%-19%) and linoleic (C 18:2, 68%-72%) fatty acids. Palmitic (C 16:0, 6%), stearic (C 18:0, 5%), and minor amounts of myristic (C 14:0), myristoleic (C 14:1), palmitoleic (C 16:1), arachidic (C 20:0), behenic (C 22:0), and other fatty acids account for the remaining 10%. Advances in modern genetics, most importantly induced mutations, have altered the fatty acid composition of sunflower oil to a significant extent. Treating sunflower seeds with γ- and X-rays has produced mutants with 25%-30% palmitic acid. Sunflower seed treatment with X-rays has also resulted in mutants having 30% palmitoleic acid, while treatments with mutagenic sodium azide have produced seeds containing 35% stearic acid. The most important mutations have been obtained by treatment with dimethyl sulfate, which produced genotypes with more than 90% oleic acid. Mutants have also been obtained that have a high linoleic acid content (>80%) by treating seeds with X-rays and ethyl methanesulfonate. Of the vitamin E family of compounds, sunflower oil is known to predominantly contain α-tocopherol (>90%). Spontaneous mutations controlled by recessive genes have been discovered that significantly alter tocopherol forms and levels. The genes in question are tph1 (50% α- and 50% β-tocopherol), tph2 (0%-5% α- and 95%-100% γ-tocopherol), and tph1tph2 (8%-40% α-, 0%-25% β-, 25%-84% γ-, and 8%-50% δ-tocopherol). The existence of (mutant) genes for increased levels of individual fatty acids and for different forms and levels of tocopherol enables the development of sunflower hybrids with different oil quality. The greatest progress has been made in developing high-oleic hybrids (>90% oleic acid). There has been considerable work done recently on the development of high-oleic hybrids with altered tocopherol levels, the oil of which will have 10-20 times greater oxidative stability than that of conventional sunflower oil. While sunflower breeders work on developing hybrids with altered oil quality, medical scientists in general and nutritionists in particular will determine the parameters for the use of these novel types of oil that can improve human nutrition and be used in the prevention of cardiovascular diseases. [ABSTRACT FROM AUTHOR]

The article reports on the genetic variation and identification of molecular markers associated. It discusses that the conventional screening for disease resistance based on five separate types of resistance is efficient. It infers that the spikelet disease severity is numbered and that the metabolic profiles were recorded using gas chromatography.