Figure 2. Effect of maize plant with different intra-row spacing on the root architecture and the spread of pepper Phytophthora blight in the greenhouse.

(A) A schematic illustration of maize and pepper intercropping arrangements in the greenhouse. Maize planted with six different intra-row spacing distances (10, 15, 20, 25, 35 and 45 cm). Each plot contains two lines of maize with different intra-row spacing. Two lines of pepper were planted between the two lines of maize, and one line of pepper was sown outside of each maize line as an indicator line. Six peppers in the center of two pepper lines were inoculated with zoospores of P. capsici. The incidence of pepper Phytophthora blight in indicator lines was surveyed to show the ability of the zoospores to spread; (B) Changes in maize root architecture with different intra-row spacing distances at silking stage; (C) Effect of maize intra-row spacing on the spread of pepper Phytophthora blight in plastic houses. M and I represent pepper monoculture and pepper intercropping with maize, respectively. Means and standard errors are shown. Different letters indicate statistically significant differences analyzed using Turkey Post-Hoc ANOVA (p<0.05; n = 9); (D) The correlation analysis between disease incidence and maize root biomass in each line at silking stage.