Effects of Maturity, Genotypic Background, and Temperature on Seed Mineral Composition in Near-Isogenic Soybean Lines in the Early Soybean Production System

The objective of this study was to investigate the effects of maturity, genotypic background, and maximum temperature 20 d before maturity on soybean [Glycine max (L.) Merr.] seed mineral concentrations. A field experiment was conducted in Stoneville, MS, in 2004 and 2005, using two sets of near-isogenic soybean lines that differed in maturity genes. One set of isolines derived from cultivar Clark and the other from cultivar Harosoy. The maturity of each line within a set varied, but all had a common genotypic background. For Clark isolines, there were positive correlations (P < 0.05) between maturity and N with r = 0.83 in 2004 and r = 0.62 in 2005, and between maturity and Ca (r = 0.59 in 2004 and r = 0.89 in 2005). For Harosoy isolines, there were positive correlations (P < 0.05) between maturity and Ca with r = 0.60 in 2004 and r = 0.83 in 2005, and between maturity and B (r = 0.48 in 2004 and r = 0.72 in 2005). There was a highly significant genotypic background effect (P < 0.01) on seed N, S, Ca, K, Mg, P, and B concentrations, and maturity gene (E-gene) effect (P < 0.01) on Ca and B. Generally the contribution of genotypic background or maturity to total variation of nutrient concentrations was greater than that of temperature. This information may be useful when developing soybean germplasm with higher seed mineral content by using genotypes with a higher nutrient uptake efficiency trait as either parental lines or source material to improve existing varieties for the seed nutrition trait.