Fig. 5. Relationship between15N/Nt ratio in nodules and both efficiency in use ofthe rhizobial symbiosis (A) and P content in nodules (B) of six common bean recom-binant inbred lines inoculated with R. tropici CIAT899 and grown under sufficient(white circle) versus deficient (gray circle) P supply. The equations inserted in thegraphs describe the regression function under P-sufficiency (light gray text) and Pdeficiency (dark gray text), respectively. Data are means and standard deviation offour replicates calculated by difference between plants harvested at 15 and 42 DAT.*Significant difference at P < 0.05.