Independent Inheritance of Resistance to Corn Stunt and Maize Dwarf Mosaic in Corn1

Inbred lines of corn (Zea mays L.), resistant to corn stunt (CS) but susceptible to maize dwarf mosaic (MDM), were crossed with inbreds of the opposite genotype. The parent, F1, and F2 populations were grown in a field experiment. Plants were inoculated with maize dwarf mosaic virus and allowed to be naturally infected with the corn stunt agents. Notes were taken on severity of symptom expression for each disease on each plant. Notes were taken 7 and 14 weeks after planting for MDM and CS, respectively. Data from F2 plants did not indicate the number of genes conditioning resistance to either of these diseases. Coefficients of correlation between CS and MDM ratings obtained on individual F2 plants were extremely small and not significant. Therefore, we concluded that the resistance to these two diseases was independently inherited.