Root system architecture over time in the nine soybean genotypes: Root system width between 6 and 23 days after transplantation (A) and at harvest (B). Root density from 6 to 23 days after transplantation (C) and at harvest (D). The 95% confidence interval with local regression adjustment was drawn in transparency. In the boxplots, letters indicate significant differences among genotypes (Tukey’ ́s HSD test. P < 0.05).