SOURCES OF RESISTANCE TO GRAY LEAF-SPOT OF CORN

In 1989, 1,396 corn (Zea mays) inbreds were evaluated for resistance to gray leaf spot at Urbana, Illinois, after inoculation with Cercospora zeae-maydis. Sixty-two inbreds were selected on the basis of low disease rating, restricted lesion type, and maturity most useful for breeding programs in the midwestern United States. In 1990, selected inbreds and F-1 crosses between selected inbreds and the susceptible inbred FR1141, with the hybrid FR1141 X LH51 as a susceptible check, were evaluated. Crosses of FR1141 with inbreds CI30, CI88A, DS:74:1071, H110, Mo18W, Mo22, and TEX 1 had ratings that were nearly as good as or better than their resistant parent and significantly better than the susceptible hybrid FR1141 X LH51. Many sources of resistance to gray leaf spot are available to improve inbreds used in corn hybrids in the midwestern United States.