Windows of maize resistance
1997
Bergvinson, D.J.
Breeding for maize resistance to insects and disease has been made possible by the broad genetic range in host plant resistance (HPR). However, within a given genotype, resistance can vary considerably over the course of plant development as well as between the different plant tissues for a given stage in development. These temporal and spatial changes in HPR are also reflected in the phytochemical composition of the plant. Using leaf bioassays, the feeding preferences of European corn borer larvae for certain portions of the leaf and stages of maturity were identified. These preferences were then related to photochemical composition which included nitrogen, fiber, phenolic acid, and DIMBOA content as well as leaf toughness and epidermal cell wall absorption of ultraviolet light. Disease pests of maize are also influenced by changes in host plant chemistry, in particular the silk and kernel chemistry as it relates to Fusarium sp. Inferences on HPR strategies can be made from these types of studies which in turn can further our understanding of heritable resistance and how to screen germplasm in an efficient manner. This paper also serves to show the importance of sample position and timing when studying phytochemical mechanisms of HPR to insects and disease.
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