Comparison of Techniques for Inoculating Maize Silk, Kernel, and Cob Tissues withFusarium graminearum

Six inoculation techniques differing in the method of application of a conidial suspension and in the part of the ear inoculated were evaluated for their effectiveness in assessing maize (Zea mays) resistance to ear rot caused by Fusarium graminearum. Silk channel injection and ear-tip flooding inoculation techniques were carried out 7 days after silk emergence. The other four techniques (wound-spray, kernel-stab, pipe cleaner, and cob-tip) were carried out 15 days after silk emergence. A 7-class rating scale was used to assess disease severity at harvest. Significant differences (P < 0.05) in incidence and severity of ear rot symptoms were detected among the inbred lines and inoculation techniques. There were significant inbred x inoculation technique interactions, but inoculation techniques intended to measure the same resistance mechanism ranked inbred lines similarly in three of the four environments. All inoculation techniques except the ear-tip flooding technique identified CO325 as the most resistant inbred. Among the techniques used, the silk channel and the kernel-stab techniques appeared to be the most effective in measuring silk and kernel resistance, respectively.