Host Suitability of Commercial Sunflower Hybrids to Pratylenchus zeae.

Host suitability of commercial sunflower hybrids to Pratylenchus zeae was studied in the field and greenhouse. For comparison, one maize and one grain sorghum inbred line, both susceptible to P. zeae, were included in the greenhouse experiments. Pratylenchus zeae densities extracted from the roots of sunflower hybrids grown in naturally infested soil were low. In the first greenhouse experiment, P. zeae densities per 5 g roots and per root system were lower (P = 0.05) in four sunflower hybrids than in maize and grain sorghum. In the second greenhouse experiment, no or few P. zeae were extracted from the roots of eight sunflower hybrids grown in a sandy or sandy clay loam soil. Roots of maize and grain sorghum grown in the sandy soil supported higher (P = 0.05) P. zeae densities than those grown in the sandy clay loam soil. All sunflower hybrids tested were nonhosts or poor hosts for P. zeae.