Inoculation of Sphacelotheca reiliana Spores to Identify Maize Germplasms Susceptible to Head Smut

Abstract

This study aimed to improve the inoculation procedure with Sphacelotheca reiliana to identify germplasms susceptible to head smut of maize. During Phase I, 1.5 g of spores were introduced into a substrate roll, which was then sown at 15, 20, 25, and 30 days after inoculation in a spore-free field. During Phase II, 15 hybrids were planted on three dates in a field with head smut disease record. The tassel and ear were examined, and the number of infected plants was registered. In Phase 1, all hybrids showed the highest infection rates 25 days after inoculation. In Phase II, the highest infection percentage was observed on the first date (32.5%). Experimental hybrids 1 and 2 and hybrid DK357 showed the highest infection percentages, whereas hybrids DK2037 and DK2061 showed the lowest infection percentages. On the second date, 10 hybrids were susceptible to infection, while on the third date, the hybrids showed low infection percentages or were not infected. The disease response in the Cimarron, Experimental 3, and Antelope hybrids was relatively constant over the first two planting dates. The experimental hybrids and P4063W showed high infection percentages. On the first date, the Experimental 3, Experimental 2, P4063W and Experimental 1 hybrids showed infection percentages of 77, 65, 62 and 46%, respectively. On the second date, these percentages changed to 49, 35, 41 and 48%, respectively. The proposed inoculation method is more effective and can be employed a lower cost and with less infrastructure than previous methods.