Two experiments were carried out to evaluate the efficiency of weed con trol by herbicides, applied singly or in combination with boron (B), and the response of sunflower (Helianthus annuus L.) to fertilization with this micro nutrient. Herbicides were applied to the plots whose sub-plots involved the presence or absence of 2 kg ha-1 of B, from two different sources (H3BO3 boric acid and Na2B8O13 ·4H2O– sodium borate) mixed with the herbicides. The combinations of the herbicides and boron, preferentially from the source H3BO3, efficiently controlled the following weeds: wild poinsettia (Euphorbia heterophylla), hairy beggarsticks (Bidens subalternans), and alexandergrass (Brachiaria plantaginea). The application of B in association with herbicides increased the content of this micronutrient in the soil and consequently in sun flower leaves. The combined application of herbicides and boric acid appears to be perfectly suitable for controlling weeds while increasing the mineral nutrition of sunflower.

A four-year field experiment was carried out to study the effects of differ ent N levels on yield, yield components, N uptake and seed quality of sunflower genotypes grown in semiarid Mediterranean conditions. Five genotypes (four commercial hybrids and one newly selected genotype) and three N fertilization levels (0, 50 and 100 kg N ha-1) were compared over four years (1996, 1997, 1998 and 1999). Sunflower plants were taken at flowering time and their dry weight, leaf area index and total N content were determined. At maturity stage, yield, yield components, oil content, protein content, N uptake and seed quality were determined. The obtained results indicated significant differences in yield perform ance (seed, oil and protein production) throughout the years (from 2.52 t ha-1 in 1996 to 3.81 in 1999), confirming the need to use recommended genotypes and adjust fertilizer rates to crops requirements, especially in the Mediterra nean environment where weather conditions are unpredictable and inconsist ent. In fact, the genotypes showed different behavior in all years regarding total N uptake, seed, oil and protein production, indicating that the sunflower crop is responsive to agronomic management. The highest level of N fertilizer resulted in the best sunflower performance although, due to variations in year and genotype, fertilizer N could be applied according to total annual N uptake. Finally, the N uptake and the diameter of head were the most important parameters that influenced sunflower yield performance.

Occurrence and parallel variation of free indole 3 acetic acid (IAA) and gibberellins (GA3) in different organs of Helianthus annuus L. have been inves tigated at various development stages by the gas chromatography method. The highest concentration of IAA was found in aboveground organs while the IAA concentration in roots was much lower. Genotype variation has also been determined. It has been established that the percentages of free IAA in roots, leaves, inflorescences and flowers were much higher in parent lines than in the F1 hybrid. These data demonstrated a direct correlation between auxins and hybrid vigor. The obtained results demonstrate the spatial (roots, leaves, inflores cences and flowers) and temporal distribution (during various ontogenetic phases) of auxins, which confirm their taking part in polarity formation and indicating dominant centers of activity in sunflower.

The subspecies Subrhomboideus (Rydberg) Heiser of the perennial hexa ploid species Helianthus pauciflorus (rigidus) was crossed with the cultivated sunflower H. annuus L. The crossability rate was high. Seeds and hybrid plants were obtained in both directions of crossing. The F1 plants had an inter mediate type of heritability, but they strongly resembled the wild parent in most important biomorphological characters. All plants were with the peren nial cycle of growth. During the second and third years, a large number of plantlets emerged from sleeping buds on the root system of F1 materials. The hybrid nature of the F1 plants was confirmed through cytological, RAPD and electrophoretic analyses of seed storage proteins. Polymorphism of H. annuus, H. pauciflorus ssp. subrhomboideus and theirs F1 hybrids was studied by RAPD. The results showed introgression of the subspecies Subrhomboideus in the hybrid progeny. It was established that the subspecies carried Rf genes for cms Pet-1. As a result of self-pollination, sib-pollination and back-crossing to cultivated sunflower, F2, F3, F4 and BC1 progenies were obtained. Some of the obtained hybrids were included in a program of development of lines for heter osis breeding in sunflower.

Cytogenetic peculiarities during the passing of meiosis were studied in anthers of 7 interspecific F1 hybrids obtained by crossing annual wild species (Helianthus annuus, H. praecox, H. argophyllus) with the cultivated sun flower. The hybrids derived from H. annuus and H. argophyllus were characterized by a low frequency of aberrations (6.5-8.6%), which gives evidence of a good balance of the chromosome complex of these hybrids. The hybrids derived from the crosses between H. praecox and the cultivated sunflower were considerably less stable because of a high frequency of aberrations in meiosis (29.6-50.0%).

Sunflower seed aging during storage affects seed vigor and content of fatty acids. In order to reveal severity of their influence, the following vigor tests were applied: standard laboratory germination test, cold test and Hiltner test. Five sunflower lines submitted to natural aging process for six and 12 months were tested under conventional storage and controlled conditions. The obtained results revealed that seed aging damaged the seed, which adversely affected seed vigor; most reliable results were obtained by the cold test and content of linoleic acids.

The paper is a synthesis of research issues concerning oil content in sun flower seeds and the relationship between seed oil contents in parent lines and their hybrids.

Photosynthetic activity is the decisive factor of yield increase in sunflower plants. This activity determines the application of agrotechnical measures such as row spacing and plant density. Experiments have proved that agrotechnical measures allow to control the growth, development and yield of sunflower hybrids and varieties. Row spacing and plants density affect the index of photo synthesis and the yield of sunflower agrophytocoenoses. Cultivation of sun flower at the row spacing of 15 cm in different variants of plants density increased the yield of the hybrid Zaporozhskiy 9 by 0.11-0.70 t/ha, of the hybrid Kharkovskiy 58 by 0.62-1.1 t/ha, of the variety Lider by 0.24-0.59 t/ha, of the variety Prometey by 0.20-0.63 t/ha as compared with the cultivation in agrophytocoenoces at the row spacing of 70 cm.

Sunflower is an important edible oil crop. Its yield on dry lands of West Asia-North Africa is low due to limited rainfall at the time when this crop is in full growth during May-June, thus supplementary irrigation (SI) must be used. However, this region lacks river/canal water and irrigation, when possible, is from underground water storages, which, due to their quantitative scarcity, have to be used judiciously. This trial was conducted to assess the minimum SI application needed to produce optimum economic yields. The study was made for three years (1995-1997) at Tel Hadya, ICARDA, in northern Syria, on a soil characterized as fine clay (montmorillonitic, thermic Calcixerollic Xero chrept) with a pH around 8.0. We tested two open pollinated varieties, HO-1 and Record, and three water level treatments, rainfed, 50% of crop water requirement and 100% of crop water requirement. Effects of environment (years), variety and water level were observed on plant height, head and stem diameter, 200-seed weight, leaf area and sunflower grain yield. The results show that plant height, head diameter, stem diameter and leaf area differed significantly due to year effects while seed weight and yield differed non-signifi cantly. The cultivars were significantly different only regarding seed weight and stem diameter. Grain yield obtained under rainfed conditions was highly significantly lower than those obtained under SI, with both lower and higher quantity of irrigation water. The average yield increase with 50% SI was 150% and with 100% SI was 312%. However, the yield difference between the two irrigation levels was 66%. This trial showed that 50% SI irrigation level can increase the yield substantially and economically, and can be resorted to in the absence of water for full irrigation.

Sunflower (Helianthus annuus L.) is an important oilseed crop. It was grown on more than 20 million hectares in the world in 1997, of which 60,000 ha were in Iran. There is a potential for substantial increase in sunflower acre age and production on dry land in Iran by applying optimum management practices. Two important management considerations are selecting row and plant spacings able to provide adequate plant density that will maximize seed yields and minimize seeding costs. This study conducted in 1998 investigated the effect of plant density (38,000 to 100,000 pl/ha) in combination with row (50 and 75 cm) and plant spacing (20, 25, 30, 35 cm) on agronomic traits of two open pollinated sunflower cultivars, Progress and Record, grown under rain-fed conditions at two dry land research stations, one located at Gachsaran (a warm region) and another in Sararood (a semi-cold area of Iran). Sowing was performed on moist soil after effective rains in early spring. Higher plant populations produced higher yield compared with lower populations in both locations. Average yield was higher at Gachsaran than at Sararood, this can be due to varietal differences. The rainfall during the trial year was 854.6 mm at Gachsaran and 613 mm at Sararood.

Sunflower is the main crop in the rotation system in Trakya region which is located in the European part of Turkey. As this area is the main sunflower producing region in Turkey, a large survey was organized there in order to determine the uses of agricultural resources and their effectiveness in sun flower production in Turkey. Data compiled via a questionnaire circulated to 182 agricultural enterprises in Edirne, Kirklareli and Tekirdag provinces in the region in the 2005 production year were used in the study. The examined locations were classified in 3 groups according to input uses for sunflower pro duction per unit area. Cobb-Douglas type production functions were calculated for each group. It was found that farm size/land area was the main production factor in each 3 groups. In the analyzed enterprises, the sum of production elasticity coefficients was found to be 0.978 for group I (Tekirdag), 0.938 for group III (Edirne) and 0.856 for group II (Kirklareli). The production elasticity coefficients for inputs were positive for group I and the coefficients for herbi cide, fertilizer and hoeing costs were negative for group II. For group III, the production elasticity coefficients for seed, fertilizer and hoeing costs were negative.

A new strain of Verticillium dahliae, the fungus causing Verticillium leaf mottle and wilt, was identified from northwestern Minesota in 2002. The new strain or biotype is characterized by its ability to overcome the single, domi nant V-1 resistance gene employed in oilseed and confection hybrids. Samples collected in 2003 from diseased plants confirmed the new biotype also exists in Manitoba, Canada. Limited survey, conducted in September 2004, identified the new strain in roughly one-quarter of fields showing Verticillium wilt in North Dakota. In greenhouse trials in 2004/5 we tested 221 cultivars for reac tion to the new Verticillium strain. One entry from the USDA Plant Introduc tion collection, developed in Russia as VNIIMK 8883, was immune and would be an ideal source of resistance. Other commercial oilseed hybrids from the U.S., Argentina and Europe, were also noted with ratings of 0.5 or lower on a 0 to 5 scale. On a related note, another fungus, Phialophora asteris F. sp. heli anthi, was isolated from oilseed sunflower plants showing leaf mottle symp toms in Minot, North Dakota in 2002, and presumed to be due to Verticillium dahliae. In greenhouse inoculations, Phialophora produced leaf mottle symp toms on sunflower lines with and without the V-1 gene, which were very similar to those incited by V. dahliae. Proper identification of this pathogen from plants displaying leaf mottle symptoms will be necessary to avoid confusion between the two pathogens.

Verticillium dahliae (Kleb) is a major sunflower disease (Helianthus annuus L.) in Argentina. The aim of this study was to evaluate different lines of EEA Pergamino sunflower breeding program for Verticillium reaction in order to find effective sources of Verticillium resistance. A method of seedling inoculation was applied to evaluate the performance of 689 lines. The scale was R (resistant), MR (medium resistant), MS (medium susceptible), AS (highly susceptible). The lines were grouped according to genetic background and percentages of lines in each class were calculated. The major variability was detected in P4. A higher percentage of resist ance was obtained in selfed populations than in crosses of different lines. The crosses of local × exotic lines had better performance than the respective groups. Variability for Verticillium resistance was obtained in different sources of germplasm.

The effect of several soil tillage methods (plowing at a depth of 20-25 cm, chiseling at 30 cm and plowing at 20 cm plus sub-soiling at 50 cm factorially combined with three biennial rotations (wheat-sugarbeet; wheat-sorghum; wheat-sunflower) were studied between 2000 and 2005. Sugarbeet confirmed the supposed increased need for deep tillage, whereas sorghum and sunflower were less sensitive. With dry soil chiseling was enough to prepare a seed bed compared with plowing plus sub-soiling, whereas with moist soil, shallow plowing gave the best results in sorghum but not in sugarbeet. Plowing plus sub-soiling requires more energy and it could be justified only in sugarbeet. Wheat yielded better after sugarbeet and sunflower than after sorghum. Mini mum tillage was as efficient as shallow plowing for wheat seed bed prepara tion.

Fertilization may help crops to yield better. To determine whether mete orological and soil conditions influence the productive response of nitrogen fer tilization in sunflower, a study was conducted in an Italian interregional project (BIOLI). The effects of nitrogen fertilization on two commercial high oleic varieties (Carnia and PR 64 H 61) was investigated in North East (Udine) and East Central Italy (Osimo) during 2005. Nitrogen fertilization was not effective in Osimo under rainfed and drought conditions, whereas the highest N level gave the best yield in Udine in wet and irrigated conditions. In both locations plant size was positively influenced by fertilization. No differences were observed among varieties in Osimo, whereas in Udine the locally selected hybrid had the best performance. Nitrogen fertilization is suggested only in good weather conditions and in nitrogen poor soil. Under drought conditions nitrogen influences plant growth but not yield.

Sunflower yield is strongly dependent on the cultivar cropped, especially under drought conditions. This study was conducted to determine the best sunflower hybrid to be recommended to farmers. Yield and culture traits response of 13 sunflower hybrids were investigated in Osimo, East Central Italy, for four years. Based on the four-year average, Barolo had the highest mean yield, 30.8 t/ ha, but it was not significantly higher than the other 9 cultivars. Among the best, only one was a high oleic variety (Proleic 204). Gloriasol had a signifi cantly high oil content (530 mg/1000 mg). Oil yield was mainly influenced by achene yield. Differences among the hybrids were large, indicating the need to assist farmers in their cultivar selection.

Sunflower (Helianthus annuus L.) has become the most important oil crops in Uganda. The area under production has increased dramatically since the mid 1990s. In the 1970s and 1980s, sunflower breeding research was based on evaluating imported hybrids. This did not show any impact in com mercial production. Recent evaluation of hybrids led to the release of PAN 7351 from South Africa which is now in full production and being imported by Mukwano Seed Company. Serere Agricultural Research Institute (SAARI) received a few hybrid parental lines for hybrid development. Some bottlenecks like branching and fertility of female lines led to slow development of hybrids from these parental lines. A few crosses have been made and yields of over 2,000 kg/ha have been attained. Uganda is now in position to produce her own hybrid seed.

Oil yield per unit area is the ultimate target in growing high-oil sunflower genotypes. A research was carried out to determine planting date effects on oil yield, using three sunflower hybrids (Miro, Rimi, Pobednik), eight planting dates and two vegetation periods. The experiment used the RCB design with four replications. Oil yield as product of grain yield and oil concentration was expressed in kg/ha. Oil yield was predominantly influenced by the year of grow ing (91.5%). The influence of planting date on yield amounted to 4.3%. All sources of variation were highly significant, except hybrid and interaction hybrid × year. On average, the hybrid Rimi had the highest mean value for oil yield. Oil yield was higher in 2004 than in 2005.

Sunflower nitrogen fertilization recommendations in South Africa are based on yield goals. In this approach, soil nitrogen supply is not taken into account with the result that nitrogen fertilization recommendations from differ ent institutions are in disagreement. Delta yield, the difference between a well fertilized crop and a zero nitrogen fertilized control, was found to be a more reliable indicator of the economic optimum nitrogen rate for maize than the yield goal, in three different countries. In seeking improved accuracy, this study was done with the aim to compare delta yield with yield goal as estima tors of the economical optimum nitrogen fertilization rate for sunflower. Reported results of fifty fertilization trials, each representing a specific year and locality, were collected, the nitrogen response curves fitted and the optimum nitrogen rates, corresponding yields and delta yields calculated. Grain yield responded to applied nitrogen significantly at only twenty-five of these trials and with the calculated optimum nitrogen rate within the limits of the applied nitrogen. Only 27% of the variation in the optimum nitrogen fertiliza tion rate was explained by yield goal compared with 87% by delta yield, making it a far more reliable indicator of the optimum nitrogen rate. The relationship between delta yield and the optimum nitrogen rate is best described by a power function: Y=X0.669 with Y the optimum nitrogen rate and X the delta yield, both measured in kg per ha.

Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) are antioxidant enzymes which have important role in the metabolic reactive oxygen species (ROS) and defence against oxidative stress damage. Antioxidant enzymes activity increases in plant cells as a response to environmental stresses. The objective of this study was to evaluate the effects of micro nutrients application on the antioxidant enzyme metabolism (SOD, CAT and GPX) in sunflower under drought stress. This experiment was carried out at Golmakan Agriculture Research Station (Iran) in 2005, using a split plot randomized complete block design with four replications. Irrigation as a main factor at three levels (normal, low stress and high stress) and six micronutrient treatments (control, Fe, Fe+Zn, Fe+Zn+Cu, Fe+Zn+Cu+Mn, Fe+Zn+Cu+Mn+B) as sub-plots within the main plots. Base fertilizers (N,P,K) and micronutrient treatments also used as required on the basis of the soil test. Results showed that the activity of these enzymes was significantly different (a= 5%) between control and stress treatments. The antioxidant enzymes concentrations were increased at 11-31% under high stress. Also there were significant differences (a= 5%) between control and micronutrient treatments under different enzyme concentrations. The antioxidant enzymes concentrations were increased at 48-89% level with Fe+Zn+ Cu+Mn treatment. The results showed that under drought stress micronutrients application increase drought resistance in sunflower.

The metabolism of triacylglycerols (TAG) and their conversion into new triglycerides and polar lipids such as linolenic acid take place during the first phase of development of Helianthus annuus L. seed after seeding. Oleate desaturase and linoleate desaturase are two major enzymes responsible for the synthesis of these compounds. To determine whether enzymatic mechanisms function the same in catabolizing seed store lipids of normal and mutant sunflower lines, modifications of fatty acids composition of seeds and the initial stages of growth (seeding-VE) cultivated under conditions of controlled temperature were assessed. The increase of linoleic acid content during all stages of development in a mutant line revealed a higher activity of oleic acid desaturase (∆12-desaturase) in transforming oleic acid to linoleic acid probably due to higher availability of the substrate of this enzyme in this line; however, its amount increased moderately in a normal line. The activity of FAD2-3 in developing sunflower seeds is recognized even two days after seeding (DAS) in both lines; however, linolenic acid accumulation starts seven DAS.

Both plant breeding programs and food industry need to develop rapid and low cost methods to characterize sunflower prior to allotment. Near infrared spectrometry (NIRS) is widely used to classify sunflower lots according to fatty acid content. This study proposes an extension of NIRS potential use con cerning sunflower by tocopherol and phytosterol content quantifications. Approximately 800 samples of ground sunflower kernels were scanned by NIRS at 2 nm intervals from 400 to 2500 nm. For each sample standard meas urements of tocopherol and phytosterol contents were performed. Total tocopherol content was obtained by high performance liquid chromatography (HPLC) coupled with a fluorescence detector while total phytosterol content was assessed by gas chromatography (GC). For tocopherol, the calibration data set ranged from 190 to 1280 mg mg kg-1 oil (mean value around 615±165 kg-1 oil) whereas for phytosterol content, the calibration data set ranged from 125 to 765 mg 100 g-1 oil (mean value of 334_75 mg 100 g-1 oil). The NIRS calibration showed a relative good correlation (R2=0.62) between pre dicted by NIRS and real values for total tocopherol content but a poor correlation for total phytosterol content (R2=0.21). These results indicate that NIR spectrometry could be useful to classify high and low tocopherol containing lots despite possible improvement of calibration by inclusion of a larger number of data in tocopherols NIRS calibration. In contrast, the determination of phytosterol content by NIRS needs more investigations. In this study, only one mathematical calibration was tested and other mathematical methods are under investigations.

Significant manifestation of heterosis for agronomically important traits is the main precondition for obtaining productive sunflower hybrids (Škorić et al., 2006). Development of high-yielding and stable sunflower hybrids based on interspecific hybridization requires knowledge of heterotic effects occurring in the F1 generation. Heterosis for seed yield per plant, total seed number per head and 1,000-seed weight was studied in interspecific hybrids obtained by the line × tester method. The seven female inbred lines used in the study had been developed by interspecific hybridization, while the three male restorer inbreds with good combining abilities were used as testers in the form of fertility restorers. Twenty-one F1 hybrids were obtained by crossing each tester with each female inbred line. A trial with the lines and F1 hybrids was set up at Rimski Šančevi. Experiment Field of Institute of Field and Vegetable Crops in Novi Sad using a randomized block design with three replications. Our study found significant differences in the mean values of all the traits under investigation. Heterosis values for seed yield were positive and highly significant relative to parental average (98.4-274.1%) as well as better parent (55.8-223.2%). Considerably less heterosis was found for total seed number per head (69.6-203.7%) relative to parental average and better parent (47.6-183.3%). With 1,000-seed mass, the values ranged between 26.5% and 48.8% relative to parental average and from -42.4% to 30.9% relative to better parent. This study could prove useful in the development of new high-yielding sunflower hybrids based on interspecific hybridization.

Twenty-nine populations of five wild annual sunflower species (H. annuus, H. petiolaris, H. argophyllus, H. praecox, H. debilis and H. neglectus) were screened for resistance to Plasmopara halstedii by the whole seed immersion method. Resistant populations were then crossed with cultivated sunflower. Analysis of meiosis and pollen viability in parent and F1 populations was used for characterization of F1 interspecific hybrids, as self-fertilization can also occur. Resistant plants were found in the populations of the species H. annuus and H. argophyllus. The percent of resistant plants in H. annuus populations was 9.09-100% and in H. argophyllus 50.00-57.14%. Irregular chromosome pairing in diakinesis was found in 0-20.83% of meiocytes of the F1 interspecific hybrids, with quadri- and univalents present. Pollen viability of male fertile interspecific hybrid plants was 10.21-98.85% in H. annuus and 39.90-52.47% in H. argophyllus. The obtained results suggest that annual wild sunflower species can be used to obtain resistance, or at least to increase the tolerance of cultivated lines to Plasmopara halstedii.

The cultivated sunflower (Helianthus annuus L.) is one of most important oil crops of the world. Although sunflower is primarily grown for extraction of its seed oil there is a limited production of non-oilseed sunflower types which are used in confections industry or as bird feed. The objective of this research was development of hybrids with high and stable oleic acid content and modified tocopherol composition, with high values for the two most important agronomic characters (seed yield and oil yield) and high tolerance to Phomopsis. The incorporation of the gene Ol+tph1 into these genotypes has led to the development of high-oleic hybrids with altered tocopherol profiles. Oil of these hybrids has a much longer shelf-life than standard sunflower oil. The process of incorporating the genes Ol+tph2 and Ol+tph1tph2 into highly productive sunflower genotypes is under way. The most important results of this line of research are the newly developed female lines with the oleic acid content in oil over 90% and the male lines (restorers) with an oleic acid content in the 89-93% range. Using these lines, hybrids will be developed whose oleic acid content in oil will exceed 90%.

Wild species of sunflower (Helianthus annuus) play an important role in the genetic improvement of this oleaginous crop since they have different characters of economic importance to be transferred into the cultivated form using interespecific hybridization. The purpose of our present research program is to preserve and characterize the genetic resources of both naturalized and exotic wild sunflowers having an agronomic interest. One of the first steps was to describe different accessions of annual wild species for biotic stress in order to detect potential resistance sources. H. petiolaris is one of the wild sunflower species that can be found in Argentina and we had selected before a certain number of these species on the basis of their Sclerotinia sclerotiorum responses on leaves and stems. This genetic material was then inoculated on leaves and stems but with Phomopsis helianthi, a fungus which produce stem canker in sunflower. This work shows the variability of brown necrotic responses after Phomopsis inoculations on H. petiolaris leaves and stems. Some half-sib families were detected to have good disease tolerance to Phomopsis as well as Sclerotinia and they will be backcrossed in order to increase the diversity for this disease resistance in the cultivated germplasm.

ASAGIR represents the sunflower value chain in Argentina. It is a non profit organization targeted to increase production efficiency, product and by products quality, and promote product diversification. Nowadays ASAGIR is working in programs and activities according to the concept of food value chain, which is intended to foster the integration of all productive sectors, from seed production to oil and by-products. Main activities include support to scientific research activities and market studies, organization of workshops and scientific or technical events, participation in international meetings and groups of study, and bulletins and web page edition intended to make the results of these studies available. Argentine Sunflower Association, ASAGIR has studied the characteristics of sunflower chain in Argentina, characteristics of different sectors involved in each step, including economic topics, to understand how to increase value and enhance sunflower business in Argentina. It is assumed the model could be projected on a global level.