Figure 2. Disease incidence and index of soybean red crown rot affected by C. parasiticum infection, rhizobia and AMF inoculation as well as P level in the sand culture experiment.

A) disease incidence; B) disease index; C) pictures of C. parasiticum infection, rhizobia and AMF inoculation on tap root (left) and lateral roots (right); D) microsclerotia in the roots. LP, 15 µmol P added as KH₂PHO₄; HP, 500 µmol P added as KH₂PHO₄. Disease incidence and index was measured as described in Materials and Methods. All the roots were inoculated with C. parasiticum (see Materials and Methods for details). −R−A: roots without AMF and rhizobia inoculation; +R−A: roots inoculated by rhizobia; −R+A: roots inoculated by AMF; +R+A: roots inoculated by rhizobia and AMF. Each bar represented the mean of eight replicates with standard error. * and ** stood the significant difference between two P levels analyzed by one-way ANOVA. *: significant at 0.05 (P<0.05); **: significant at 0.05 (P<0.01).