EFFECT OF ANTHRACNOSE STALK ROT ON GRAIN-YIELD AND RELATED TRAITS OF MAIZE ADAPTED TO THE NORTHEASTERN UNITED-STATES

Anthracnose stalk rot (ASR), caused by Colletotrichum graminicola (Ces.) Wils., has been recognized as a threat to North American maize (Zea mays L.) production since the early 1970s. The purpose of this study was to determine the effect of ASR on grain yield and yield-related traits of eight maize inbreds adapted to the northeastern United States. The inbreds and their crosses were grown at locations in New York, Delaware and Pennsylvania. Treatments were organized in a split-plot design, with genotypes as main plots and inoculation with C graminicola or no inoculation as subplots. Results are reported for grain yield, number of ears (EARS), and 500-kernel weight (KWT). The effect of inoculation was not significant for grain yield or the two yield-related traits, although the location x inoculation interaction was significant for grain yield. These results show that physiological reduction in grain dry weight attributed to ASR is highly dependent on environment. Significant differences among parents were found for EARS and KWT. General combining ability was significant for KWT, while specific combining ability was significant for KWT and grain yield. Average heterosis was significant for all four variables.