Genotypic Variation on Root Growth and Nutrient Uptake in Corn and Soybean

Abstract

Core Ideas Drought‐tolerant corn increased root length up to 33% over conventional corn. Differences in root growth among soybean genotypes were site‐specific. Nutrient dilution effect occurred in both corn shoot and root, but not in soybean. N, P, Mn, and Zn concentrations were higher in the root biomass for soybean compared with corn. Larger root systems can help crops to explore more soil volume and increase nutrient uptake. The objective of this study was to evaluate potential differences in root system growth of two corn (Zea mays L.) and two soybean [Glycine max (L.) Merr.] plants of contrasting genotypes. Two experiments were conducted as part of this study (greenhouse and field). The corn genotypes used in the study were considered as drought tolerant (DT) and conventional (CR)–not drought tolerant; whereas soybean genotypes were considered as highly suitable for poorly drained soils (PD) and suitable for well‐drained soils (GD). During the growing season, shoots and roots biomass were recorded and analyzed for total nutrient concentration. Roots were scanned and processed to measure root length, surface area, diameter, and volume. In the greenhouse, corn root length and volume showed greater values for the DT at the VT growth stage compared with the CR. The DT also showed higher N, Mn, and Zn uptake. In the field, the DT showed greater root length at one location. For soybean, the GD showed increased root surface area and volume at one location when compared with the PD. The PD showed higher Zn uptake than the GD. Furthermore, evaluations of nutrient dilution as a function of root biomass was similar to those observed for shoot biomass for corn, but not clear for soybean. This study emphasizes the importance of root system evaluations among different genotypes as it can help on strategies to increase nutrient uptake by crops.