Effect of Corn (Zea mays) Genotypes Which Vary in Maturity Length onStriga hermonthicaParasitism

Corn (maize) genotypes which varied in days to maturity were evaluated for level ofStriga hermonthicaparasitism in western Kenya during three seasons. Fifteen genotypes, with a wide range in days to maturity, were grown in fields heavily infested withS. hermonthica.Early and late-seasonStriganumbers and corn grain yield were used to evaluateStrigaparasitism. There was considerable variation in the timing and amount ofStrigaattachment among seasons. Days to silking and late-seasonStriganumbers were correlated (P ≤ 0.05) in all experiments although only weakly in one of the experiments. Grain yield was negatively correlated with days to silking in two of three experiments as were yield and early seasonStriganumbers. Although earlier-flowering genotypes consistently supported lessStriga, they did not always yield more than the later-maturing genotypes due to confounding effects of yield potential and adaptation. There was considerable variation inStrigaparasitism among genotypes within maturity groups, and the relative response of genotypes varied between seasons. These data suggest that in some seasons early maturing genotypes have potential to reduceStrigaattack in heavily infested areas and yield more than later-maturing genotypes.