Oleic Hybrids Research Articles

Development of new high oleic Sunflower (Helianthus annus L.) hybrids and its genotype × environment interaction across temperature regimes

The present investigation was undertaken to assess the stability of 30 sunflower hybrids for oleic acid content along with four commercial checks across three temperature regimes of Karnataka, India over two seasons, rabi/summer 2020-21 and rabi 2021. The phenotypic stability of sunflower hybrids was analyzed by AMMI model. The AMMI biplots delineated one promising hybrid combination which exhibited stable expression of high oleicacid content, with pooled mean of all six environments revealing 73.06 per cent of oleic content. The identification of this particular hybrid combination served the purpose of this study of deriving the stable high oleic hybrid across temperature regimes.

Изменчивость репродуктивных признаков у генотипов подсолнечника с различным содержанием жирных кислот и токоферолов в семенах

The aim of the work was to study the reproductive characteristics of sunflower genotypes with altered composition of fatty acids and tocopherols in seeds. Studies were conducted in 2017, 2020 and 2022 at the VNIIMK, Krasnodar. The material was a high oleic hybrid of sunflower Oxy with a modified composition of tocopherols, as well as its maternal VK 876 and male VK 195 parent lines. Moreover 19 samples of the genetic collection were studied. The assessment of bee attendance showed significant hereditary variability from 98 to 0.5 bee/plant/hour. The Oxy confirmed a low level of bee attendance, on average, 14 bee/plant/hour. The lines with the maximum values of bee attendance MVG-8 and K 2479 showed a greater amount of nectar and a high level of its sugar content than the genotypes with the minimum values of bee attendance. The data obtained confirm the main role of the nectar of tubular flowers in the pollinator attractiveness. The Oxy had a low pollen grain diameter of 29 microns, a high proportion of defective pollen grains of 37%, a low level of self-fertility of 19% and the seed setting of 47%. The transmission of these negative traits to the hybrid comes from the maternal line of VK 876, and not from the male form of VK 195, which is characterized by normal reproductive traits. The content of oleic acid did not significantly correlate with any of the seven reproductive traits. Correlation coefficients were established: the amount of nectar – bee attendance (0.57), the amount of nectar – sugar content of nectar (0.55), the amount of nectar – the number of defective pollen grains (-0.55), the number of defective pollen grains – self-fertility (-0.72), the number of defective pollen grains – seed setting (-0.47) and a self-fertility – seed setting (0.60). Mutations of high oleic Ol and the composition of tocopherols tph1 and tph2 did not have a pleiotropic effect on reproductive traits in the lines of the genetic collection.

The effect of phomopsis on the formation of seed yield of sunflower hybrids

Purpose. To determine the resistance of sunflower hybrids to phomopsis and the formation of their adaptability to growing conditions.Methods. Artificial inoculation, histological, field.Results. The hybrid turned out to be early ripening with 108 days, while in hybrid ‘Hector’, the growing season was 109 days. Other hybrids: ‘Suchasnyk’, ‘Selianyn’ and ‘Antratsyt’ had a longer vegetation period, which was in the range from 115 to 122 days. In terms of vegetation, the highest height was obtain in the hybrid ‘Antratsyt’ 167.6, while in the hybrid ‘Selianyn’ 162.2 cm. Other hybrids (150.2) and ‘Hector’ (157.9) had slightly lower plant height. Moreover, such a hybrid as ‘Suchasnyk’ formed the lowest figure of 144 cm. The oilseed of all the hybrids under study was at a sufficiently high level and the highest rate was in ‘Suchasnyk’ (51.9 %). The highest weight of 1000 seeds was in the ‘Hector’ hybrid, which was 74.1 g, and in the ‘Selianyn’ hybrid, it was the lowest (69.9 g). The affection with phomopsis, as well as other diseases, led to a decrease in both the yield and the quality of the harvested seeds. The percentage of sunflower plant damage varied in the following sequence: ‘Antratsyt’ (8.5 %), ‘Hector’ (11.6 %), ‘Siuzhet’ (12.5 %), ‘Suchasnyk’ (14.5 %), ‘Selianyn (16.9 %).Conclusions. The yield increase +320 kg/ha in comparison with the standard variety was obtained. Also at a sufficient level, a crop of oleic hybrid ‘Hector’ was formed, amounting to +0.46 t/ha with the oil yield of +227 kg/ha. The lowest seed yield was obtained in the ‘Antratsyt’ hybrid, with a yield increase of +0.17 and oil yield+ 70 kg/ha.

Synthesis and evaluation of high oleic hybrids in relation to oil quality and seed yield in sunflower (Helianthus annuus L.)

Sunflower (Helianthus annuus L.) is one of the most important oilseed crops of the world. Oils with high oleic content maintain oil oxidative stability and better dietary properties for customers. Such oils are known to help in reducing the cholesterol level and prevent heart diseases. In this study, 49 sunflower hybrids were synthesized using seven CMS and seven restorer lines and evaluated along with check hybrid RSFH-1, during 2015-16 at Main Agricultural Research Station, UAS, Raichur. Among parents, four CMS lines had 60-79 per cent oleic acid and four restorer parents had 66 to 85 per cent oleic acid. Out of the 49 hybrids evaluated, two hybrids, CMS-3109A x RHA-1390 (82.01%) and CMS-3114A x RHA-64NB (81.29%), exhibited higher oleic acid proportion., and these two hybrids also showed higher seed yield per plant, high oil content, high test weight and early maturity.

Hybrid sunflower seed yield, composition and deterioration after chemical desiccation

The impact of chemical desiccation on yield showed contrasting results depending on seedmoisture content at the time of application. Its effects on seed deterioration are still unknownand could be modified by seed composition. Objectives were to evaluate the impact of chemicaldesiccation on: i) hybrid sunflower seed yield and composition at harvest time, ii) seeddeterioration during long-term storage and iii) the relationship between seeds deterioration andoil or oleic acid content. Six hybrids including low, mid and high oleic were evaluated in threeexperiments. Two treatments were applied on female lines at 27-30% seed moisture:(i) spraying with Paraquat and (ii) detaching heads with a knife. Control remained in the fielduntil 10% seed moisture. Seeds were stored during 19 months under room and cold chamberconditions. Yield, number of seeds and hybrid seed composition (thousand seed weight, kernelpercentage, oil and acid oleic content) were determined. Seed deterioration during storage wasanalyzed by germination and vigour. Paraquat advanced harvest by 35-43 days, withoutaffecting yield or seed composition. During storage the germination of Paraquat treatmentsremained above that of control, without differences between storage conditions, while vigourremained above control only in cold chamber, for low oleic hybrids. Associations betweendeterioration (germination and vigour) and oil or oleic acid content, were not significant.Desiccation with Paraquat allows advanced harvest without yield losses or modifications in seedcomposition. The deterioration of desiccated seeds was lower and independent from oil andoleic acid content.

Fatty acid composition of high oleic sunflower hybrids in a changing environment

High oleic hybrids of sunflower are widely cultivated around the world. The effect of temperature on oleic acid percentage of these hybrids is a concern, since oils with oleic acid percentage above a threshold receive a prime over the regular price. The objective of this work was to identify the main avenues for the genetic improvement of oleic acid percentage of high oleic hybrids of sunflower, both in current and future global warming scenarios. A data set obtained in a trial network allowed to explore the oleic acid percentage response to temperature of high oleic hybrids in the argentine sunflower growing region (between 29 and 38° LS, 46 trials in 15 locations during the period 2005/06–2012/2013). A similar data set was used to evaluate the variability in phenology. Mean values and stability across environments of oleic acid percentage differed among the studied high oleic hybrids. Differences in the parameter values of a sigmoid equation evidenced the variability in the response of oleic acid to temperature. Oleic acid percentage was simulated with a model that included this equation coupled to a phenology module, for different sowing dates and locations with contrasting temperature, under current conditions and a global warming scenario. It was possible to identify a low number of temperatures and field environments useful to reproduce the rankings of hybrids obtained with a wide range of temperatures. This information could be used to phenotype for high oleic percentage with a low number of experiments and reduce the efforts to identify better high oleic genotypes. Simulations show that the maximum oleic acid percentage is currently not attained in 50% of the studied hybrids in some sowing dates, even at the warmest locations, while in a future global warming scenario it would not be attained in 30% of the studied hybrids in the colder locations. Sensitivity analysis was performed for parameters of the sigmoid equation and the phenology module determining when the critical period for fatty acid composition occurs. In both in current and future scenarios, phenology parameters showed a null or low effect on oleic acid percentage. Two parameters of the sigmoid equation showed a significant impact, which differed between current and future scenarios. Simulations suggest that the stability of oleic acid percentage could still be a concern in the future. However, selecting for key parameter values for a given scenario could help to obtain better high oleic hybrids of sunflower.

Adaptability of sunflower (Helianthus annuus L.) high oleic hybrids to different Italian areas for biodiesel production

Currently the biodiesel chain is promoted by the European energy policy. For the Italian scenario the sunflower is one of the most important crop to be considered for biodiesel production but the chain is not fully profitable. This problem could be solved with the increase of farm incomes through a proper valorization of by-products. From this point of view the oilseed crop is not considered only for oil production but also for producing multiple products with the same economic value. This is the main inspiring concept of the Extravalore project. The sub-project “Raw Materials” investigated about the possible influence of different agro-technics performed in three distinct geographical environments (Northern, Central and Southern Italy) on the characteristics of by-products obtained from sunflower crop.A national net of experimental tests was set during the 2010–2013 period in order to evaluate the adaptability and the potential production of high oleic sunflower hybrids. 7 seed companies supplied the 20 genotypes assessed in total (18 high oleic hybrids and 2 as control), 11 of them were evaluated all the three years.Achene yields of tested high oleic hybrids were extremely variable: from 2.05tha−1 to 4.04tha−1 in Northern Italy, from 2.50tha−1 to 4.24tha−1 in Central Italy and from 2.09tha−1 to 2.68tha−1 in Southern Italy. For this reason, it was necessary a precise characterization of varieties before their cultivation. The cultivar screening showed general difficulty for high oleic hybrids to reach the performances of achene and oil yields of the conventional ones. In particular, LG55.57HO and PR64H31 resulted the best high oleic cultivars for Northern Italy; many of the high oleic tested cultivars performed well for Central Italy and also for Southern Italy but with a higher variability. The highest potential production was registered in Central Italy; Northern Italy gave decreased but similar results, despite the different latitude; in Southern Italy the productions were 20–30% lower, even with the irrigation support. All high oleic tested cultivars showed oleic acid content in lipid fraction always above the 84% in Central Italy, meaning a stability of the character, very important for the biodiesel production.

Effect of growth temperature on the high stearic and high stearic-high oleic sunflower traits

We investigated variability in the response of oil fatty acid composition to temperature among high stearic and high stearic-high oleic sunflower (Helianthus annuus L.) genotypes. Two experiments were conducted with high stearic (including the CAS-3 mutation) and high stearic-high oleic inbred lines (including both the CAS-3 and the high oleic Soldatov mutations). Plants were cultivated in pots with soil, irrigated, and fertilised. Plants were exposed to different day/night temperatures during grain filling: 16/16°C, 26/16°C, 26/26°C, and 32/26°C. Oil fatty acid composition was determined by gas–liquid chromatography in seeds harvested after physiological maturity. Higher temperature during grain filling increased palmitic and oleic acid percentages and reduced stearic and linoleic acid percentages, suggesting some modifications on enzymatic activities. When the high oleic mutation was included, the variation in stearic and oleic acid percentages in response to temperature was reduced but not the variation in palmitic acid concentration. Variations in fatty acid composition in high stearic genotypes were mainly associated with night temperature as reported previously for traditional and high oleic hybrids. Knowing the effect of temperature on oil fatty acid composition in traditional and mutated genotypes is useful for selecting the environment in which to produce grains with the desired oil quality.

Yield performance and grain lipid composition of standard and oleic sunflower as affected by water supply

Sunflower has potential in Mediterranean farming systems because of the modest auxiliary input requirement, appreciable productivity and quality of raw material. These aspects are affected by the interactions among genetic, environmental and agronomic factors, which have not been fully explored. Therefore, the effects of four water regimes as proportion of crop evapotranspiration (0%, 33%, 67%, 100%) on grain yield and its components, oil yield and grain lipid constituents, i.e. fatty acids (FAs), unsaponifiable matter (UM), phytosterol (Phy), policosanol (PC) and tocopherol (Toc) fractions of a standard and an oleic sunflower hybrids were assessed in a 2-year field experiment. The relationships between crop productive traits and oil quality features were also analysed. In general, as the water supply (WS) increased grain yield and related traits as well as achene's lipid synthesis and oil yield of each genotype (G) were positively affected. Conversely, the significant WS × G interaction found for the grain lipid composition indicated that the hybrids responded to different water treatments by modifying the proportions of major FAs as well as the UM and its total Phy, PC and Toc concentrations, with non-univocal percentage changes of their respective compounds. An increase of the unsaturation ratio of oil occurred when water (rainfall + irrigation) input increased, although at different level for each hybrid according to their genetic constitution. Because of the influence of warm climatic conditions, standard hybrid provided oil with an oleic–linoleic acid balance similar to that of mid-oleic typology. Within the oil UM, which contains also bioactive metabolites involved in the resistance of the plant to various abiotic constrains, total Phy concentration increased and total PC concentration decreased as the water (rainfall + irrigation) input was reduced, but to a different extent in the two hybrids. The most effective combinations of studied treatments for total Toc concentration were standard hybrid irrigated at both 33% and 67% of ETc replacement and oleic hybrid without irrigation. The results suggest that growing sunflower in a water-limited Mediterranean-type environment is possible to produce satisfactory grain and oil yields with an appropriate use of irrigation. Some oil quality characteristics suitable for different industrial uses could also be achieved by a combination of WS with standard or oleic typology of sunflower hybrids.

Que sait-on du déterminisme de la qualité des huiles du tournesol face aux nouvelles attentes ?

Sunflower oil is widely consumed in France and Spain. This oil has a good reputation among consumers, due to its high polyunsaturated fatty acid content. Thirty years after its discovery, the oleic mutation (high C18:1 contents) has now reached agricultural production, with fast increasing surfaces for the last three years. The challenge is now the production of very high oleic (> 90%) sunflowers and new fatty acid profiles, such as high linoleic, palmitic, stearic or stearic + oleic hybrids, which are of high interest for chemistry or food industry. The problem is now the stability of the expression in varying genetic backgrounds, and the understanding of environmental effects. Minor components are also a main strength of sunflower oil: its high tocopherols (Vitamin E) content (0,5 to 1%) is all the more interesting for nutritionists that they be almost exclusively α-tocopherol (> 95%), which is the most vitaminic active component. Nowadays, the unraveling of tocopherols biosynthesis and its key points of regulation is in progress. New tocopherol profiles have been recently obtained. Higher protective effects are attributed to γ- or δ-tocopherols. They could increase the stability of oils or margarines. Genetic progress for total content is possible, as in sunflower like in other oilseed crops, heritability is rather high (> 0.7). Sunflower oil also contains twice as much phystosterols as olive oil (3 vs 1,5%), and mainly β-sitosterol. Major mutations of this pathway can induce penalizing phenotypic modifications: 1) campesterol is the precursor of plant hormones brassinosteroids, and 2) stigmasterol/campesterol ratio is also implied in plant growth regulation. However, hybrids can significantly differ in their total content. Either for fatty acids or minor components, breeding programs for new profiles, or higher contents, need high throughout oil extraction and analysis. Chemometric analysis offer interesting solutions despite their need of large sets of reference analysis.

Some economically important properties of sunflower cultivars (Helianthus annuus L.) in the field trials performed at Biotechnical faculty

The basic parameter of re-introduction of this crop into the crop rotation in Slovenia is testing and trials of sunflower cultivars (Helianthus annuus L.), that could be suitable for the growing conditions in Slovenia, for the purpose of organic production and for the production of healthy food for consumers. On the experimental field at Biotechnical Faculty, in the period from 2002 to 2006, we were testing certain economically significant properties of five sunflower cultivars: Kernal, Kongo, Delija, Goleador and Iregi szürke csíkos. Seeds were sown by hand to the parcel in the size of 3 m x 11.8 m. Under the growing conditions in central Slovenia the genetic potential of hybrids for the production above 4 t of seed/ha was almost reached and closely approached by the hybrids Kongo and Kernal with average yields 3.5 t/ha and 3.3 t/ha. Yields of Delija and Goleador hybrids were about 1 to 1.2 tons lower, but mutually comparable. The lowest yield (1.6 t/ha) was given by Iregi szurke csikos variety, which is mostly grown by the producers in Slovenia, mainly because it is used and sold as a bird feed. In the year 2003, the fat content in the seed obtained from the hybrids, reached from 38 to 42 %, for Iregi szurke csikos variety it was only 33 %, on the other side - in the year 2005 - the fat content in the seed obtained from the hybrids was higher, that is 39 to 45 %, and for the Iregi szurke csikos variety the average was the same as in the year 2003. The highest fat content in the seed was reached by highly oleic hybrid Goleador, that is 42 % in the year 2003 and 45 % in 2005; for this hybrid, during this two years of the trials the 78- to 79-percent content of oleic acid in the oil was a little lower than its genetic potential, which is above 80 %. Regarding the use of the crop - for the cold pressed oil - the most important cultivars are the highly oleic hybrid Goleador and semi-oleic Delija, and for the bird feed instead of the Iregi szurke csikos variety we could sow Kongo and Kernal hybrids, not only due to their higher yields, but also due to higher fat content. Experts can advise producers how they can increase their production of seeds and oil only on the basis of tested, high quality and accessible sunflower assortment.

Some economically important properties of sunflower cultivars (Helianthus annuus L.) in the field trials performed at Biotechnical faculty

The basic parameter of re-introduction of this crop into the crop rotation in Slovenia is testing and trials of sunflower cultivars (Helianthus annuus L.), that could be suitable for the growing conditions in Slovenia, for the purpose of organic production and for the production of healthy food for consumers. On the experimental field at Biotechnical Faculty, in the period from 2002 to 2006, we were testing certain economically significant properties of five sunflower cultivars: Kernal, Kongo, Delija, Goleador and Iregi szurke csikos. Seeds were sown by hand to the parcel in the size of 3 m x 11.8 m. Under the growing conditions in central Slovenia the genetic potential of hybrids for the production above 4 t of seed/ha was almost reached and closely approached by the hybrids Kongo and Kernal with average yields 3.5 t/ha and 3.3 t/ha. Yields of Delija and Goleador hybrids were about 1 to 1.2 tons lower, but mutually comparable. The lowest yield (1.6 t/ha) was given by Iregi szurke csikos variety, which is mostly grown by the producers in Slovenia, mainly because it is used and sold as a bird feed. In the year 2003, the fat content in the seed obtained from the hybrids, reached from 38 to 42 %, for Iregi szurke csikos variety it was only 33 %, on the other side - in the year 2005 - the fat content in the seed obtained from the hybrids was higher, that is 39 to 45 %, and for the Iregi szurke csikos variety the average was the same as in the year 2003. The highest fat content in the seed was reached by highly oleic hybrid Goleador, that is 42 % in the year 2003 and 45 % in 2005; for this hybrid, during this two years of the trials the 78- to 79-percent content of oleic acid in the oil was a little lower than its genetic potential, which is above 80 %. Regarding the use of the crop – for the cold pressed oil – the most important cultivars are the highly oleic hybrid Goleador and semioleic Delija, and for the bird feed instead of the Iregi szurke csikos variety we could sow Kongo and Kernal hybrids, not only due to their higher yields, but also due to higher fat content. Experts can advise producers how they can increase their production of seeds and oil only on the basis of tested, high quality and accessible sunflower assortment.

Genetic variability in the response of fatty acid composition to minimum night temperature during grain filling in sunflower

It is not known if the response of the oil fatty acid composition to temperature is similar among sunflower hybrids, especially among traditional hybrids. The objective of this work was to asses the genetic variability of the response of the oil fatty acid composition to temperature during the period 100–300 °C day after flowering among sunflower hybrids. Seven traditional hybrids and a high oleic hybrid were grown in several locations of Argentina. With the same hybrids two experiments were carried out in growth chambers where the plants were exposed to different day–night temperatures during grain filling. From these field and growth chamber experiments wide ranges of variation of temperature and oil fatty acid compositions for each hybrid were obtained. The concentration of oleic acid in sunflower oil showed a sigmoidal response to minimum night temperature from 100 to 300 °C day after flowering, increasing almost lineally within a given range of temperature. Outside this range, the concentration of this fatty acid remained merely constant. The same mathematical expressions characterized the response of oleic acid concentration to temperature in both, traditional and high oleic hybrids. The same expression also described the response of other fatty acids to temperature in all the hybrids. Differences between hybrids were observed for the minimum and maximum concentration of oleic acid and also for the maximum slope and range of the response. Since the sum of oleic + linoleic acids increased with temperature, increasing temperature reduced the concentration of saturated fatty acids and behenic acid. Genetic variability in the response of these fatty acids to temperature was observed. The results presented here show that it is possible to obtain sunflower oils of very different qualities combining the genetic variability in the response of the fatty acid composition to temperature and the climatic diversity under which sunflower is cultivated.

Downy mildew (Plasmopara halstedii) infection in high oleic sunflower hybrids in Northern Italy

SUMMARY 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.

Comparison of Fatty Acid Metabolism of Two Oleic and One Conventional Sunflower Hybrids: A New Hypothesis

AbstractStudies on oleic sunflower (Helianthus annuus L.) were carried out in order to determine which mechanism produces oleic and linoleic acids in oleic hybrids. The fatty acid composition of different lipid fractions (structural and storage forms) was followed during the achene development of three hybrids including cv. Santiago (non‐oleic hybrid), cv. Olbaril and cv. Trisun 870 (high oleic hybrids). In addition, a simple physiological model of fatty acid accumulation was developed. In order to complete this biochemical approach, a molecular study of desaturase gene accumulation has been preformed. The evolution of oleic and linoleic acid contents in achenes revealed the lack of Δ12‐desaturase activity in oleic hybrids and also indicated differences between oleic genotypes related to linoleic acid content in the first days after pollination and until maturity. Molecular studies (using Northern blot analysis) confirmed that the Δ12‐desaturase transcript was not expressed at the same time in oleic hybrids. These observations were confirmed by studies on the selective dispatching of oleic and linoleic acids in different lipid fractions during achene development. Trisun 870 showed a very low content of linoleic acid in triglycerides throughout achene maturation, whereas Olbaril presented a higher initial content followed by a rapid decrease. These results led us to put forward a new hypothesis for fatty acid biosynthesis in the oleic sunflower hybrids.

Diversified composition of sunflower (helianthus annuus l) seeds within cultural practices and genotypes, hybrids and populations

Environmental factors, mainly temperature and water availability, play a major role with genotype factor in oil quality of sunflower. To manage seed composition through cultural practices and genotype choice under scarce water resources is one way to provide an added-value to crop yield and to diversify uses for edible oil or for non food applications in Mediterranean regions. The study of interactions between crop management and genotypes for yield and also for major seed compounds (oil, protein and fatty acids) was conducted in the Rotation-Quality device in Toulouse-Auzeville (France) during three experimental years. Two standard populations and four hybrids (two oleic and two standard), well adapted to cropping systems in Morocco and France, were investigated in conventional and late sowing dates associated with non-irrigated and irrigated treatments. For all genotypes, delay of sowing improves protein content and seed weight but decreases yield, stronger for populations compared with hybrids whereas oil content is not depressed. Globally, in irrigated crop, only the percentage of protein in seed dry matter decreases. The oleic and linoleic acids contents in standard hybrids seeds are sensitive to sowing date whereas oleic hybrids and populations' contents are relatively more stable. Indeed, oleic acid content in standard hybrid seeds increases with a concomitant reduction of linoleic acid content in the case of late sowing. Water regime does not affect the oleic and linoleic acids. The delay in sowing decreases stearic and palmitic acid contents in oleic hybrid seeds, and in standard hybrid seeds only palmitic acid content. These saturated fatty acids contents are not affected by irrigation treatment. Close negative correlations between oleic and linoleic acids and between oleic and palmitic acids are present in all genotypes and treatments. Our results suggest that there exist different genotype behaviors for fatty acids accumulation in response to crop management.

Effect of saline water on oil yield and quality of a high oleic sunflower ( Helianthus annuus L.) hybrid

Sunflower is a species moderately tolerant to salt stress and is currently cultivated in dry areas where salinity can be a threat. The effect of salt stress on achene yield has been investigated, but no information exists about its effect on the oil fatty acid composition. The aim of this paper was to evaluate the changes in oil yield and fatty acid composition in a high oleic hybrid submitted to different salinity levels of irrigation water. Furthermore, since the addition of a leaching fraction to the irrigation volume may be relevant to prevent excessive soil salinization, a water regime equal to 1.5 maximum evapotranspiration (1.5 ETc) was compared with the restoration of evapotranspiration (1 ETc). A pot experiment was carried out in a greenhouse with a high oleic sunflower hybrid (Platon) grown on a loam soil under two irrigation regimes with five salinity levels of irrigation water (0.6, 3, 6, 9 and 12 dS m −1). At harvesting, seed production, oil yield and fatty acid composition were determined. The percent seed yield decrease per unit increase of irrigation water electrical conductivity (ECw) was higher for 1 ETc (7%) than for 1.5 ETc (5.8%). Oil yield showed a significant decrease from 38.3 to 3.4 g per head on increasing salt stress and a marked increase of about 50% with the higher irrigation volume. Under our experimental conditions with a medium textured soil, this result confirms the importance of leaching to limit salt accumulation along the soil profile, thus reducing seed and oil yield drop under salt stress. Concerning fatty acid oil composition, under all the adopted experimental conditions, both oleic and linoleic acid accounted together for 90% of total fatty acid concentration, while stearic and palmitic acid were about 4%. No great differences were observed in fatty acid composition between the two irrigation regimes. With the higher irrigation volume, only a slight decrease in linoleic and gadoleic acid and an increase in arachidic acid were observed. The only significant differences among saline treatments were observed for oleic and linoleic acid. Oleic acid showed an increase from 82.8% in the control to 86.8% at the highest salinity treatment. Inversely, for linoleic acid a progressive decrease from 6.9 to 2.8% with increasing salinity level was observed. These results will be discussed in the light of a possible inhibition of oleate desaturase occurring under salt stress.

Night temperature affects fatty acid composition in sunflower oil depending on the hybrid and the phenological stage

Fatty acid composition is affected by plant genotype and environmental conditions with temperature a major effect. The effect of night temperature during different periods of fruit filling on the fatty acid composition of sunflower oil from hybrids with different potential oleic acid content has never been studied. This information is needed if we are further to improve oil quality. A traditional, a mid oleic and two high oleic hybrids were sown in the field on 3 November 1998. The traditional hybrid was also sown again on 22 November 1998. In each experiment, four treatments were applied; a control and three treatments in which night temperature was increased 6.9 °C at three different consecutive periods of 200 °C day after flowering. A third experiment was carried out in growth chambers using the same genotypes as in the previous experiments plus another high oleic hybrid. Three day–night temperatures (16–26, 22–20 and 26–16 °C) were applied to plants from flowering to physiological maturity. In general, oleic acid percentage was higher with higher night temperature and was not related to daily minimum temperature. The largest variation in oleic acid percentage was observed in the traditional hybrid and the lowest in the high oleic hybrids. Higher oleic acid percentage was associated with an increase in night temperature early during fruit filling. Variation in oleic acid percentage was related to variation in linoleic acid percentage in all experiments.

Changes in seed yield and oil fatty acid composition of high oleic sunflower ( Helianthus annuus L.) hybrids in relation to the sowing date and the water regime

Sunflower is one of the most cultivated oil crops in the world. Recently, high oleic acid cultivars have been developed whose oil has higher oxidative stability and better dietary properties than standard genotypes. In Mediterranean environments where water deficit frequently occurs, early sowing and irrigation are used to overcome environmental constraints due to water scarcity. Since, in the literature, the data on the effect of these agronomic techniques on sunflower oil quality are scarce and contrasting, the aim of this paper was to evaluate the effect of the sowing time and the water regime on seed yield and oil quality of high oleic hybrids in a Mediterranean environment. For this purpose, two high oleic hybrids (Platon and Vyp70) sown in spring at two different dates were cultivated in southern Italy under two water regimes (irrigated and non-irrigated) in 1996 and 1997. Yield and its main components were positively affected by irrigation and by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed under irrigation. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing and under irrigation, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds.