Bird damage and tannin content in grain sorghum hybrids under different environments.

In a comparison of bird-resistant and non-resistant sorghum cv., those containing tannin suffered no damage. Damage was significantly correlated with flowering date but not with seed colour. In trials near Plains and Experiment, Georgia there was large variation and the response of non-resistant hybrids varied. Brown-seeded, non-resistant hybrids contained no detectable tannins. Tannin content varied with environment and grain which grew at low autumn temp. varied with hybrid. It was concluded that resistance or tannin content were not always expressed to the same extent in different environments