Screening for ergot resistance in sorghum.

Experiments were conducted at Arsi Negele, Ethiopia, during the 1988 and 1989 rainy seasons to determine a suitable combination of sorghum panicle trimming (a method used to remove pollinated spikelets), inoculation, and bagging to develop an ergot resistance screening technique. Results showed that the most suitable method was a single inoculation of nontrimmed panicles when anthesis began in a panicle, followed by bagging. Comparison of resistance evaluation methods suggested that susceptible genotypes could be identified by a simple and rapid visual ergot rating on a 1-5 scale, where 1 = no ergot and 5 = more than 50% spikelets in a panicle infected. However, resistance of genotypes should be confirmed by counting infected and healthy spikelets in a few primary branches of panicles. Screening of 213 Ethiopian sorghum accessions led to the identification of six ergot-resistant lines—ETS 1446, 2448, 2465, 3135, 4457, and 4927—that are well adapted to the highlands of Ethiopia.