Inoculation Techniques for Identifying Resistance in Sorghum Genotypes to Sorghum Ergot

Abstract

Abstract Seven inoculation methods were tested at multiple field sites with different climates in Texas and Mexico to determine the technique most suitable for routine screening of sorghum (Sorghum bicolor (L.) Moench) germplasm for resistance to Claviceps africana (causal agent of sorghum ergot). A single spray or sponge inoculation before flower initiation followed by bagging of the panicles for seven days was the most reliable technique for identifying ergot-resistant sorghum genotypes. This method ensures that unfertilized ovules and infection sites were exposed to the pathogen at the time of greatest vulnerability, thereby reducing the influence of flowering characteristics. This method is repeatable and rapid, thus providing a useful procedure for germplasm evaluation. Disease symptoms on sorghum genotypes are expressed within a reasonably short period. Compared with the other methods, inoculated and bagged panicles resulted in a significantly higher percentage of ergot-infected florets in all envir...