Effect of Maturity On Seed Nutrient Composition in the Early Soybean Production System as Measured On near-Isogenic Soybean Lines.

Nutrient status in soybean (Glycine max L. Merr.) seed is important because it may determine seed quality. The effect of maturity on seed nutrients in soybean has not been well investigated in the Early Soybean Production System because maturity is generally confounded with genotypic background effects. Therefore, the effects of maturity on nutrient concentrations in seed were investigated in two sets of near-isogenic soybean lines derived from either ‘Clark’ or ‘Harosoy’. When  mean values were compared, the Clark isolines accumulated more N, Ca, Mg, B, Mn, and Zn than the Harosoy isolines. However, the Harosoy isolines accumulated more K, P, and Fe than did the Clark isolines. This pattern was consistent in 2004 and 2005.  For Clark isolines, there were significant positive correlations between maturity and N, Ca, and Mn (N, r=0.83 in 2004 and r=0.62 in 2005; Ca, r=0.59 in 2004 and r=0.89 in 2005; Mn, r=0.62 in 2004 and r=0.87 in 2005).  For Harosoy isolines, there were significant positive correlations between maturity and Ca, B, and Mn (Ca, r=0.60 in 2004 and r=0.83 in 2005; B, r=0.48 in 2004 and r=0.72 in 2005; Mn, r=0.46 in 2004 and r=0.75 in 2005).
The results indicate that nutrient content in soybean seed is significantly influenced by maturity and that individual isolines may accumulate different levels and types of nutrients, depending on their time of maturity. The effect of temperature on nutrient composition variability cannot also be excluded.  This information can be beneficial to breeders to select for nutrient-efficient soybean germplasm with higher nutrient seed qualities.