The ability of some sunflower species to survive and thrive in shifting sand dunes with an annual precipitation of 50 mm could be of value for cultivated sunflower, a crop often grown in arid regions. The genus Helianthus comprises 51 species and 19 subspecies, with 14 annual and 37 perennial species, all native to North America. The objective of this study was to collect achenes from as many populations as possible of desert species, specifically annual H. anomalus, H. deserticola, H. niveus ssp. canescens, and perennial H. niveus ssp. tephrodes from the desert southwestern USA and make them available for future research and improvement of cultivated sunflower. The first exploration for H. anomalus and H. deserticola took place from September 16 to 23, 2000, covering 4100 km in three states, Utah, Arizona, and Nevada; while the second exploration concentrated on H. deserticola populations in west central Nevada, taking place between June 20 to 23 and August 15 to 18, 2005. The third exploration for H. niveus ssp. tephrodes took place from February 26 through March 5, 2005, covering 2200 km in southern California and adjacent Arizona. Only one population of H. deserticola from Utah and two populations of H. anomalus from Utah were collected in 2000. The 2005 exploration in Nevada resulted in the collection of achenes from 13 popu lations of H. deserticola. In 2005, five populations of H. niveus ssp. tephrodes were collected from the Alogodones Dunes in California. One population of H. niveus ssp. canescens was collected from Yuma, Arizona, near the US-Mexico border, with three additional populations collected from the Pinta Sands area of Arizona, which is the northernmost extension of the Gran Desierto of Son ora, Mexico. Achene samples of each collection are maintained and distributed from the USDA-ARS National Plant Germplasm System, North Central Regional Plant Introduction Station, Ames, Iowa. The limited number of desert species populations collected will provide basic germplasm for further research dealing with improving drought tolerance in cultivated sunflower.

Four sunflower species, Helianthus annuus, H. argophyllus, H. debilis and H. tuberosus, were characterized at the molecular level using the plastid trnH-psbA intergenic spacer. The trnH-psbA sequence was selected with the aim of developing a “DNA barcode” system (Kress et al., 2005) as a tool for species and specimen identification. The plastid region was PCR amplified with specific primers and sequenced with an ABI Prism 3730 Automated DNA sequencer. Intraspecific and interspecific sequence variation was evaluated to assess the resolution of the technique. Sequencing of both forward and reverse strands allowed for a high base calling accuracy and overcame the problem of polymerase slippage within microsatellite regions. After sequence editing, a very low (or absent) intraspecific variability was detected, whereas interspecific variability due to SNPs, indels and SSR length was sufficient for an unambiguous identification of each species.

This study was conducted to evaluate the behavior of some high oleic sunflower hybrids towards the race of Plasmopara halstedii present in the environment and to analyze the main climatic factors affecting development and spread of the disease in order to draw up the basis for a prediction model of disease incidence. The race was determined by means of artificial infection of differential inbred lines in a growth chamber experiment and a field trial was also done to study the effects of the factors genotype, sowing time and seed dressing on the infection percentage of P. halstedii during different sunflower growing stages. The Pl genes responsible for resistance to race 700, detected in the trial area and named according to the international code, were absent in all the high oleic hybrids studied, which, however, manifested a partial resistance to downy mildew, probably due to the partial polygenic, non-qualitative and non-specific resistance to the race detected. Seed treatment with metalaxyl helped to limit the severity of P. halstedii attack to 5% of plants infected, but with a maximum of 19.6% in the susceptible check. Concerning the environmental conditions, water availability did not result as being limiting for the infection, whereas the most favorable mean air temperatures during the 5 days following sowing ranged from 10 to 15°C.

Two near-isogenic lines of sunflower, resistant (+Pl6 gene) and suscepti ble (-Pl6 gene) to downy mildew were used in this paper. Secondary infection with a suspension of Plasmopara halstedii spores was done on the plants in the phase of first pair of leaves. In the samples taken 12 h after infection, con tent of phenolic compounds in methanolic extracts from frozen leaves was ana lysed by HPLC. POD activity was determined spectrophotmetrically and POD isoforms by isoelectrophoresis. Constitutive level of phenolic compounds and their accumulation after infection were higher in the susceptible than in the resistant line. Increased POD amount in leaf, constitutively present in NS-H-26R, was in correlation with increased guaiacol-dependent POD activity and low total phenolics con tents. After infection, guaiacol- and chlorogenic acid-dependent POD activity significantly increased in both lines. Scopoletin-dependent POD activity was induced upon infection only in NS-H-26R. IEF electrophoresis revealed existance of four anionic isoforms of peroxidase in leaves of both lines. The main isoform with pI 5 was particularly intesified in the resistant line. In conclusion, scopoletin-dependent POD activity that was induced upon infection only in resistant NIL indicates a specific role of POD in coumarin metabolism that is possibly connected with the presence of Pl6 gene.

Cultivated sunflower (Helianthus annuus L.) is susceptible to Sclerotinia sclerotiorum (Lib.) de Bary. H. petiolaris Nutt is a wild sunflower species naturalized in Argentina. The objective of this work was to evaluate the responses of some accessions of H. petiolaris to S. sclerotiorum inoculation in order to detect potential sources of resistance to be used in cultivated sunflower. An experiment was carried out at the UIB’s experiment field. Inoculations were made on leaves and stems. Lesion mean on leaves was 22 mm and 24 mm on stems. The accession GRR-252 showed mean lesions on leaves significantly longer than in GRR-250. However, there were no differences for stem inoculation. Correlation analysis indicated the independence of leaf and stem responses. Results obtained after the first experimental trial suggest the possibility of detecting some H. petiolaris accessions with a higher level of resist ance to S. sclerotiorum than others.

Fusarium fungi have grown from a minor pathogen of sunflower crop to a major problem of sunflowers in Russia. The aim of this work was breeding for resistance to this new major pathogen, combining field and laboratory testing in the framework of VNIIMK hybrid sunflower breeding program. Four segre gated hybrid combinations selected on the basis of their field resistance to different pathogens were used as breeding material. Three of them were double cross combinations: F3 R-14 × (VK-591 × VK-539), F4 VK-623 × (HA-385 × VK-653) and F4 (VK-678 A × VK-464) × VK-541, the fourth one was a cross F3 VK-680 × O.P. variety Leader. It was shown that combination of laboratory testing and individual selection can rapidly improve the Fusarium resistance of a segregated population - the share of families without plants with Fusarium damage symptoms was 62.5% among the selected plants offspring while only 18.2% of such families were found in the breeding nursery the next year after selection. As a result, a number of new breeding lines were developed that exhibited no Fusarium symptoms in the field.

Influences of genetic background, ontogenesis and environment on tocopherol mutations in sunflower were estimated in this study. The content of α/β tocopherols varied from 40/60 to 60/40% in seeds of different inbred lines containing the tph1 gene. The lines containing the tph2 gene ranged widely in α/γ tocopherols, from 0/100 to 80/20%. A double mutation showed variability in different inbred lines in α/β/γ/δ-tocopherol contents from maximum expressivity of 0/0/60/40 to minimum 40/25/25/10%, due to incomplete expressivity of tph2. Seed maturation from 10 to 38 DAF influenced tocopherol composition in both normal and mutant genotypes by increasing the α-tocopherol content. The content varied from 81 to 97% in a normal genotype, from 33 to 50% in tph1 mutation and from 0 to 6% in tph2 mutation. Tocopherol mutations were shown to express their phenotype in different parts of a plant. All roots, hypocotyls, leaves, pollen and callus from the seeds, hypocotyls and leaves had normal, tph1, tph2 and double mutation tocopherol profiles depending on the genotype. The only exception was the absence of tph1 expressivity in the green tissue of the leaves. The experiment with day/night temperatures varying during seed development from 20/18 to 30/26°C showed an increased α-tocophe rol content from 39 to 48% in tph1 mutation. Both a normal genotype (about 97% of α-tocopherol) and tph2 mutation (about 98% of γ-tocopherol) were constant in these two temperature regimes. Genetic background was the main fac tor that influenced the expressivity of tph2 in sunflower.

An analysis of DNA microsatellite sequences of 17 sunflower inbred lines and hybrid combinations developed at VNIIMK has been conducted. Nine of the10 studied microsatellite loci were polymorphic, with the average number of alleles per locus of 2.2. One locus was monomorphic. Dominant type of inher itance was found in two loci, codominant in seven. At the level of similarity between lines from 0.19 to 0.97, individuality of each line and hybrid combination is revealed. Their molecular genetic passports were made on the basis of the nine loci. Suitability of the 9 loci for genetic purity tests of sunflower seeds in commercial lots has been shown. The seven codominant loci are suitable for definition of hybrid vigor.

Reliable analytical methods are necessary in order to determine different quality parameters of sunflowers achenes and to realize their optimum utilization in food and non-food industries. For this aim, different near-infrared methods have been developed for ground and intact high-oleic sunflower achenes. These methods determine simultaneously the important quality parameters like oil and protein content and the composition of fatty acids. The methods are adequately exact and more time- and cost-saving than the conventional reference analysis. In addition to further optimization of the NIRS methods, transfer of the calibration-equations will be worked out. This will lead to a better utility for all those concerned with cultivation, marketing and breeding of sunflowers.

The use of fuels derived from vegetable oils represents a potential opportunity to meet EU Commission guidelines promoting renewable energy utilization. This is particularly true for Mediterranean countries where farmers are well familiarized with oil crops. Sunflower is one of the most adapted crops to dry conditions typical of Mediterranean environments. The oleic acid content in sunflower oil seems to be a suitable character for biofuel production with regard to fuel oxidative stability. For the same reason, the high oleic varieties are considered particularly promising. In this study the effect of climatic condi tions and agronomic practices on oleic acid content of sunflower seeds is investigated with respect to the Southern Italy regions. Effects of high temperature, water deficit, irrigation water quality, sowing time and genotype on oil yield and quality are evaluated. Finally, the potential of sunflower cultivation for bio fuel production in the light of the recent European agricultural policy is discussed.

In some sites of Central Italy wild sunflowers are spreading from marginal areas into cropped fields. Crops like maize, tomato, tobacco, alfalfa are often infested with wild sunflowers. Hybrid sunflower crops are also infested with wild material. Plants and populations of wild sunflower also spontane ously grow at the edge of the fields, and along the ditches and roads. We have observed that wild sunflower is partially dispersed by its seed, but possibly it can propagate vegetatively by its perennial basal stalk when it survives the mild winter seasons. We have evidence that sunflower seeds maintain germination capacity for years after being plowed into the soil. This wild sunflower phenotypically resembles H. annuus, but the strong root system is not usual for an annual sunflower species. Concerning its origin, we observed variations indicating naturalization by either an introgression process involving wild species or a segregation of a hybrid variety and the enrichment of genes conferring seed dispersion and root persistence. It is pos sible that a similar process occurred a few centuries ago, after its introduction to Europe when sunflower escaped botanical gardens and began to colonize Eastern European areas.

Тhe direct organogenesis method in immature F1 embryos from sunflower was successfully applied for production of new forms from the interspecific cross Helianthus annuus (cv. Albena) × Helianthus salicifolius. After repeated selfing and continuous selection, a great diversity of new sunflower lines were developed. Some of the new lines possessed resistance to Phomopsis, Phoma, Alternaria and the parasitic angiosperm broomrape as well as very good combining ability. The hybrids developed from the new lines showed increases of the indices for seed and oil yields of 114.0% and 117.8%, respectively, compared with the mean standard (commercial hybrids Albena and Super Start), short vegetation period and reduced height. Combinations of these favorable changes are desirable in breeding work on sunflower.

The direct organogenesis method in immature F1 hybrid embryos from sunflower used for the first time in a study, was successfully applied for production of new forms from the intergeneric cross Helianthus annuus L. (cv. Albena) × H. salicifolius. A considerable number of new sunflower lines were produced after self-pollination and individual selection. Agronomic traits such as oil content in seed, 1000 seed weight, plant height, leaf width, leaf length, number of leaves, length of petiole stems, internode length, head diameter, stem diameter, diameter of branch head, number of branches, length of branches, number of ray florets, seed width, seed length, and seed thickness were investigated. After characterization of the hybrid progenies according to the indices, the conclusion can be drawn that lines 107 R, 114 R and 120 R show 76.5% intermediate phenotype in comparison with the two parental forms. The positive change was 15.5% and the negative change was 21.5%. Some of the new restorer lines were successfully used in heterosis breeding of sunflower.

Seed dormancy causes a great problem in efficient seed production of sunflower. Attempts have been made to develop simple techniques for break ing seed dormancy. In the first experiment, different techniques were evaluated using treatments such as a growth regulator, Ethrel, priming (water soaking followed by 2-3 days drying in shade), chemicals such as acetone (CH3COCH3), and potassium nitrate (KNO3) which showed the most promise. To confirm these findings, several treatments (25% acetone, 0.2% KNO3 and 24 h water soaking followed by drying) were further evaluated on 12 sunflower genotypes. Priming for 24 h in water is considered a simple and promising technique to break seed dormancy. This needs to be further confirmed using sunflower genotypes with different maturity groups and also with different periods of soaking in future experiments.