Is Seed Iron Concentration Predictive of Resistance to Iron Deficiency in Soybean?
- John V. Wiersma *a
Within the last decade, studies involving numerous crops provide strong evidence that seed Fe concentration ([Fe]) is useful for identifying genotypes possessing superior resistance to Fe deficiency. It is our opinion that using seed [Fe] is equivalent or superior to using visual chlorosis score as a measure of Fe efficiency, that seed [Fe] can be used to identify resistance to Fe deficiency in the absence of Fe deficiency or in the presence of Fe deficiency exacerbated by applying high rates of fertilizer N, that conventional plant breeding can be used to increase seed [Fe] as a strategy for improving resistance to Fe deficiency, and that planting seed [Fe] can be used as a predictor of successful (nonchlorotic) seedling establishment. International agricultural agencies, such as HarvestPlus (CIAT, Cali, Columbia), have promoted using plant breeding as an intervention strategy focused on increasing micronutrient concentrations and bioavailabilities in crops consumed by populations with known micronutrient deficiencies. Can conventional plant breeding be used to increase seed [Fe] as a strategy to reduce Fe deficiency in soybean [Glycine max (L.) Merr.]? Evidence presented in this paper combined with earlier reports indicates that Fe-efficient and Fe-inefficient varieties appear to have seed [Fe] maxima that are distinctly different and seldom exceeded; that is, soybean plants tend to maintain [Fe] in the grain within predetermined, genetically controlled limits. Seed [Fe] can be regarded as an integrated measure of resistance to Fe deficiency that is manifest at maturity and that involves the coordinate expression of several genes regulating Fe reduction and uptake, transport, and storage.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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