Genotypic and environmental effects on selenium concentration of broccoli heads grown without supplemental selenium fertilizer

Abstract

Selenium (Se) is an important trace element in human nutrition that is essential to normal health. Broccoli is known to accumulate relatively high concentrations of Se, and there is strong evidence that consumption of Se-enriched broccoli florets decreases cancer risk. In light of the above, this study was conducted to evaluate differences in Se concentration per head and total Se head content for a collection of broccoli hybrids (20) and inbreds (15) grown in field environments without supplemental Se fertilization. Our objectives were to assess the relative importance of genotype vs. environment in affecting Se levels and to determine if Se content is associated with other important horticultural traits. When analysed over three environments, there was a significant genotype effect for Se head concentration with hybrids, but not inbreds, but the environmental effect was about 10 times larger than that for genotype. Total Se content (ng/head) varied significantly among hybrids and inbreds, but as with concentration, environmental effects were also much larger for this trait. Head Se concentrations for hybrids ranged from 52.7 to 84.7 ng/g and total Se accumulation ranged from 563 to 885 ng/head. The same respective traits ranged from 49.3 to 80.0 ng/g and 678 to 876 ng/head for inbreds. There was no correlation between Se head concentration and head dry mass or days from transplant to maturity for either hybrids or inbreds. There was no evidence that Se might be diluted in broccoli heads as mass increases with cultivars that produce dense heads. Results indicate that it should be feasible to combine relatively high Se concentration or content with high head dry matter (DM), a phenotype that broccoli breeders might strive to achieve.

Selenium and its Role in Higher Plants

“…These variations do not indicate a signifi cant impact of climatic conditions, because several other factors also control the Se absorption by plants (Kabata-Pendias 2011 ). It is found that, the environmental effect on the Se concentration in broccoli was about 10 times larger than genotype impact (Farnham et al 2007 ). A variation in the Se uptake by various species of the same plant ( Astragalus ) is described by Somer and Caliskan ( 2007 ).…”

Biofortification of crops with seven mineral elements often lacking in human diets – iron, zinc, copper, calcium, magnesium, selenium and iodine

“…White and J. P. Hammond, unpublished observations), spinach (Grusak & Cakmak, 2005), chickpea (Ibrikci et al ., 2003) and onion (Alvarez et al ., 2003). Genetic variation in shoot Se concentrations has been observed in B. oleracea (Kopsell & Randle, 2001; Farnham et al ., 2007) and onions (Kopsell & Randle, 1997).…”

Selenium biochemistry and its role for human health

“…28 The use of fertilizers supplemented with Se is very effective and is easily controlled to favour accumulation by plants, and plant growth itself is generally enhanced by this element; however, plant growth may be reduced by feedback mechanisms when the Se concentration is too high. 28 Plants having the ability to accumulate high concentrations of Se such as broccoli, 29 garlic, 30 green onions, 31 green tea 32 and mushrooms, 33 are particularly adapt at obtaining natural dietary supplements following a fertilization strategy. As a consequence of Se fertilization, an increase of Se levels in milk, meat, eggs and the whole food chain has been observed.…”