VIEW ARTICLE

Resistance

Comparative Reactions of Corn Inbreds to Oospore and Conidial Inoculum of Peronosclerospora sorghi. Jeweus Craig, Research plant pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Plant Sciences Department, Texas A&M University, College Station 77843; Phytopathology 70:313-315. Accepted for publication 12 October 1979. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-313.

Corn inbreds that differed in reactions to infection by oospores of Peronosclerospora sorghi in field trials for susceptibility to sorghum downy mildew were tested for reactions to conidia of P. sorghi. The cultivars were inoculated with conidia at germination and at the first-, second-, and third-leaf stages of growth. All inbreds were susceptible at germination. Inbreds that were resistant to oospores developed resistance to conidia at or before the second leaf stage. Inbreds susceptible to oospores in the field were susceptible to conidia at the second-leaf stage. The percentages of downy mildew in corn inbreds inoculated with conidia at the second-leaf stage were closely correlated with the percentages of downy mildew induced by natural infection of these inbreds in the field.