Álvaro Fernández-Cuesta

Variability of seed quality traits in a collection of Spanish landraces of confectionery sunflower

Abstract. Confectionery sunflower (Helianthus annuus L.) has been cultivated in Spain for many years in small vegetable gardens for self-consumption, and this has created a vast genetic diversity of local landraces. The objective of this research was to assess variation in seed quality traits in a germplasm collection of Spanish local landraces of confectionery sunflower. Seed weight, kernel percentage, oil content, fatty acid composition, squalene, tocopherol and phytosterol contents, and tocopherol and phytosterol composition, were analysed in 137 landraces grown for 2 years in Córdoba, Spain. The evaluation was hindered by large differences for flowering time between accessions (>90 days), which made it difficult to separate genetic from environmental effects. The collection contained large variability for all traits evaluated. Of particular relevance were the ranges of variation (2-year averages) for squalene content (12–128 mg kg–1 seed kernel), tocopherol content (114–423 mg kg–1 seed kernel) and Δ7-stigmastenol content (7.1–35.2% of total phytosterols). Some traits were associated with specific locations; for example, all seven accessions collected in Espiel (Córdoba province) had high Δ7-stigmastenol content, although they differed for other traits. Some of the accessions evaluated in this research are valuable genetic sources for breeding programs focusing on seed and oil quality in sunflower.

Phytosterols in the seeds of wild sunflower species.

Trabajo presentado en el International Symposium on Sunflower Genetic Resources, celebrado en Kusadasi (Turquia) del 16 al 20 de octubre de 2011.

Natural variability in phytosterols in almond (Prunus amygdalus) trees growing under a southern Mediterranean climate

SUMMARY Almond (Prunus amygdalus) kernels are an important source of phytosterols that are considered essential elements for human health. Little information is available on the variability and composition of phytosterols in cultivated almond, and there is no information on wild almond such as those that have originated in Morocco. High levels of variability in phytosterol concentrations were found among 23 accessions of Moroccan almond, ranging from 1,174–2,072 mg kg−1 kernel dry weight, and from 2,184–3,582 mg kg−1 for oil phytosterol, within the ranges published for other almond genotypes. Major components of the phytosterol fraction were β-sitosterol [55.9–84.6% (w/w)] and ▵5-avenasterol [8.5–28.2% (w/w)]. Significant differences in phytosterol concentrations and compositions were observed between almond seedlings as well as between almonds of different geographical origin, possibly due to a positive effect of higher temperatures. Some genotypes, such as Al4 with high concentrations of phytosterols (3,582 mg kg−1 of oil phytosterol) could be used as parents in almond breeding programmes to add value to local products, and to improve human health.

PHYTOSTEROLS IN THE SEEDS OF WILD SUNFLOWER SPECIES / FITOESTEROLES EN LAS SEMILLAS DE ESPECIES SILVESTRES DE GIRASOL

SUMMARY Ingestion of phytosterols prevents intestinal absorption of cholesterol in humans and results in a lowering of serum cholesterol, which has stimulated the use of phytosterols as enriched food ingredients in functional foods. Sunflower seeds and oils are rich sources of phytosterols. The variation reported for these compounds in cultivated sunflower germplasm is low. As for many other traits, wild sunflower species may contain valuable unexplored variation for phytosterol content and profile. The objective of this research was to evaluate the variation for seed phytosterols in a set of 47 wild Helianthus species from the USDA-ARS collection. An impressive variation was identified for total phytosterol content (1017 to 4308 mg kg-1 seed) and proportion of individual phytosterols, particularly campesterol (5.1 to 16.3%), stigmasterol (3.1 to 23.9%), beta-sitosterol (35.1 to 72.3%), delta-5-avenasterol (1.9 to 20.5%), delta-7-stigmastenol (1.1 to 20.3%), and delta-7-avenasterol (0.3 to 10.6%). Some of the extremes of these ranges of variation have not been identified in cultivated sunflower. The feasibility of transferring genes determining interesting phytosterol traits to cultivated sunflower should be investigated. RESUMEN La ingesta de fitoesteroles reduce la absorción intestinal de colesterol en humanos y da lugar a una disminución del colesterol sérico, lo que ha promovido el uso de los fitoesteroles como ingredientes de alimentos funcionales. Las semillas y aceite de girasol son fuentes ricas en fitoesteroles. La variación publicada para estos compuestos en el germoplasma de girasol cultivado es baja. Como para muchos otros caracteres, las especies silvestres de girasol pueden contener una variación valiosa sin explorar para contenido y perfil de fitoesteroles. El objetivo de este trabajo fue evaluar la variación para fitoesteroles en las semillas en un conjunto de 47 especies silvestres de Helianthus de la colección del USDA-ARS. Se identificó una enorme variación tanto para el contenido total de fitoesteroles (1017 a 4308 mg kg-1 de semilla) como para la proporción de fitoesteroles individuales, en particular de campesterol (5.1 a 16.3%) estigmasterol (3.1 a 23.9%), beta-sitosterol (35.1 a 72.3%), delta-5-avenasterol (1.9 a 20.5%), delta-7-estigmastenol (1.1 a 20.3%) y delta-7-avenasterol (0.3 a 10.6%). Algunos de los extremos de estos rangos de variación no han sido identificados en el girasol cultivado. La posibilidad de transferencia de genes que determinan caracteres interesantes para fitoesteroles al girasol cultivado debe ser investigada.