PHENOTYPIC CHARACTERIZATION OF RESISTANCE IN ZEA DIPLOPERENNIS TO STRIGA-HERMONTHICA

Resistance to the parasitic angiosperm, Striga hermonthica, was found in a sample of Zen diploperennis, a wild relative of maize. Resistance occurred in a small proportion (10-15%) of the seed sample. Resistanc e to S. hermonthica was associated with reduced penetration of roots o f Z. diploperennis plants by the parasite or subsequent failure to dev elop normally. Most parasite seedlings formed infection structures (tu bercles) but subsequent elongation of parasite stems was severely rest ricted on some resistant Z, diploperennis plants. On other resistant p lants, S. hermonthica seedlings died before tubercles formed. Plants o f Z. diploperennis grown in soil containing S. hermonthica seeds also showed heterogeneous responses within the original sample of Z. diplop erennis. Viable seed of 2. diploperennis was produced from selected re sistant plants. The percentage of progeny resistant to S, hermonthica increased only slightly in the derived progeny, suggesting that the ge netic basis of resistance is complex.