GENETICS OF RESISTANCE IN MAIZE TO THE CORN LEAF APHID (HOMOPTERA, APHIDIDAE)

Ten inbred maize, Zea mays L., lines-A619, A632, B37, B68, B73, B96 (41:2504B), C103, Mo17, Oh45, and W153R-and diallel crosses (45 single crosses) were analyzed to determine the type of gene action involved in resistance to the corn leaf aphid, Rhopalosiphum maidis (Fitch). General combining-ability effects were more important than specific combining-ability effects. Additive-gene effects seemed more important than nonadditive-gene effects in conditioning resistance to the corn leaf aphid in the diallel crosses. This indicated that multiple genes probably are involved in corn leaf aphid resistance. Inbreds A619 and Oh45 had the best general combining ability for resistance to the com leaf aphid. The most susceptible inbreds were B37, B73, and W153R.