Natalia G. Izquierdo

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

Abstract. 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.

Oil yield components and oil quality of high stearic-high oleic sunflower genotypes as affected by intercepted solar radiation during grain filling

Abstract. High stearic-high oleic sunflower oil presents high thermal stability. This oil is an alternative to the hydrogenation process which produces trans fatty acids. The effect of intercepted solar radiation (ISR) per plant during grain filling on oil yield components and oil fatty acid composition was investigated in three sunflower high stearic-high oleic genotypes. Three field experiments were conducted and treatments to modify ISR per plant were applied during grain filling: shading, defoliating and thinning plants. Increasing ISR per plant linearly increased grain number per capitulum, weight per grain and in some cases palmitic and stearic acid percentages. In the hybrid, grain oil percentage and oleic acid concentration increased with a decreasing rate, reaching a maximum value at high levels of ISR per plant. Linoleic acid percentage decreased with a decreasing rate, reaching a minimum value at high levels of ISR per plant. Oil yield components presented heterosis. This information contributes to explain the effects of environment on yield and oil quality in high stearic-high oleic genotypes and could be used to design management practices that optimise these traits.

Sunflower Crop Physiology and Agronomy

Publisher Summary Agronomy is the science and technology of producing and using plants for food, fuel, and fiber. Crop physiology studies the structure and function of crops in relation to productivity and quality product for different uses. This chapter discusses physiology and agronomy together of sunflower crop, giving the basis for the crop management and genetic improvement of sunflower from a physiological point of view. It also discusses some differences among the physiology of sunflower and other crops. Applying ecophysiological knowledge could be helpful to optimize sunflower crop management to obtain high yields and high oil quality; to save soil water and nutrients; and to reduce the application of chemical products. It could be expected that sunflower production and crop system sustainability could be improved by a greater adoption of precision agriculture. Information systems could help to take into account the spatial heterogeneity of soil and crop properties as a decision support for process optimization. Adjustments of sowing date, plant population, and row spacing, as well as the selection of hybrid cycle are important agronomical practices to improve the performance of rain-fed sunflower crops when sown in environments with middle and high probabilities of facing drought periods.

Effect of genetic background on the stability of sunflower fatty acid composition in different high oleic mutations: Genetic background effect on sunflower high oleic oil composition

BACKGROUND The effect of genetic background on the stability of fatty acid composition in sunflower near isogenic lines (NILs) carrying high-oleic Pervenets (P) or high-oleic NM1 mutations was studied. The materials were field-tested in different locations and at different sowing dates to evaluate a wide range of environmental conditions. Relationships were established between the fatty acids and the minimum night temperature (MNT) and the response was characterized. RESULTS A genetic background effect for the fatty acid composition was found in both groups of NILs. The NM1-NILs showed an oleic level higher than 910 g kg-1 and they were more stable across environments with a zero or low dependence on the genetic background; on the other hand, high oleic materials bearing the P mutation showed lower levels of oleic acid, with a higher variation in fatty acid composition and a highly significant dependence on the genetic background. CONCLUSION The NM1 mutation is the best option to develop ultra-high oleic sunflower oil that is stable across environments and genetic backgrounds, making its agronomical production more efficient and predictable.