Seed Iron in Diverse Soybean Genotypes

Abstract

Iron (Fe) in the embryo fraction of soybean (Glycine max L.) seed is important for seedling growth. Seed Fe accumulation in 27 soybean genotypes differing in seed size was studied at two field locations. Mean seed weight was 148 mg seed −1 with mean individual genotypic values ranging from 68 to 217 mg seed −1 . Percentage of total seed dry matter in the seed-coat fraction, which was inversely correlated with individual seed weight, was 8.2%, with mean individual genotypic values ranging from 7.0% to 12.4%. Mean seed-Fe concentration [Fe] was 65 µg Fe g −1 , with individual genotypic values ranging from 48 to 81 µg Fe g −1 . Seed Fe relative to dry-matter distribution was much more concentrated in seed coats than in embryos of all genotypes. Mean percentage of total seed Fe located in the seed-coat fraction was 29%, with mean genotypic values ranging from 23% to 38%. Neither seed-Fe characteristic was correlated with individual seed weight. Seed [Fe] was not correlated with seed-manganese (Mn) concentration [Mn]. Mean seed [Fe] for the 27 genotypes was different at the two locations, presumably due to differences in available soil Fe. Both genotype and environment affected seed [Fe] of soybean. Soybean seed coats, a major by-product after oil extraction, are a possible rich source of Fe for human nutrition.

Within‐Seed Distribution of Selected Mineral Elements among Soybean Genotypes that Vary in Iron Efficiency

“…Nonetheless, the seed coat can retain approx. 30% of the soybean seed's Fe at harvest (Moraghan and Helms, 2005). With Phaseolus vulgaris L., the distribution of Fe between seed coat and embryo is known to vary among genotypes (Moraghan, 2004; Cvitanich et al, 2010).…”

“…These authors also noted that at each level of Fe deficiency, the plant's shoot [Fe] did not change but the plant's ionome (elemental composition, especially of Mn, Co, Zn, Mo, and Cd) in the shoot did change, in turn indicating the plant's Fe nutritional status. We (Moraghan and Helms, 2005; Wiersma, 2005, 2012) have observed similar differences in seed [Fe] among soybean genotypes that were rated as resistant (R), moderately resistant (MR), and susceptible (S) to Fe deficiency. Seed from R genotypes accumulated more Fe than seed from MR and S soybean genotypes.…”

“…The within seed distribution of micronutrients may be especially important for early seedling establishment and/or human consumption. Moraghan and Helms (2005) reported a pronounced, stable effect of genotype on seed [Fe]. In their research, the two genotypes with the highest and lowest seed [Fe] were the same when grown on soils that varied threefold (17 vs. 5 mg kg −1 diethylenetriaminepentaacetic acid [DTPA]‐extractable Fe) in available soil Fe.…”

Identification of new QTLs for seed mineral, cysteine, and methionine concentrations in soybean [Glycine max (L.) Merr.]

“…Variations in seed P, Mg, Ca, and manganese (Mn) in 10 different varieties of soybean were approximately 1.2-to 1.4-fold (Kleese et al 1968). Approximately 1.7-fold differences in seed iron (Fe) concentration were observed in a diversity study consisting of 27 soybean genotypes (Moraghan and Helms 2005). A few studies have reported variation in seed Cys and Met (Panthee et al 2006a, b;Sharma et al 2011) in soybean.…”

Mapping of Iron and Zinc Quantitative Trait Loci in Soybean for Association to Iron Deficiency Chlorosis Resistance

“…Shen et al (2002) showed that wheat seed high in Fe had better seedling vigor and greater chlorophyll concentration in fresh, fully expanded leaves. Moraghan and Helms (2005) evaluated seed Fe in 27 soybean genotypes differing in seed size. Genotypes differed in seed Fe concentration from 48 to 81 μg Fe g −1 .…”