Evaluation of the resistance of maize (Zea mays L.) breeding materials to sugarcane mosaic virus

Resistance of 6 maize hybrids and 10 lines to sugarcane mosaic virus was te sted under field and greenhouse conditions. In both types of tests maize pl ants were inoculated at two development stages, i. e. 3 to 4 leaves and 6 t o 7 leaves and field trials were repeated at two sowing dates. Infection af ter different inoculation treatments was assessed as a percentage of plants with symptoms of virus infection 42 days after inoculation An index propos ed by KUHN and SMITH (1977) was also calculated. In all inoculation treatments statistically highly significant differences were found between the maize materials tested both in the percentage, of in fected plants and in Kuhn index. Inoculation under greenhouse conditions at the stage of 3 to 4 leaves was the most effective, in spite of that there were strong correlation coefficients between the inoculation techniques. It is recommended to perform resistance tests in the greenhouse and to comple ment them with field tests. Of all the materials tested the least infected in all the tests were the following hybrids: Cesil, Cemax and line CE2032. In contrast, lines CE2013 and CE813I were most infected.