EFFECTS OF MECHANICAL DAMAGE ON CHEAT (BROMUS-SECALINUS) CARYOPSIS ANATOMY AND GERMINATION

A hammer mill removed most of the lemmas, paleas, and pericarps from c heat florets. Typically, the cuticular layer of the testa was the only remaining intact layer, and damage to the embryos and endosperm was s evere. A roller mill disrupted tissue organization of lemmas, paleas, and outer layers of the caryopses primarily at the cuts. Large gaps be tween the aleurone layer and testa, between testa and pericarp, and be tween the scutellum and endosperm were created. In the field, germinat ion of mill-damaged florets was reduced, and florets exhibited progres sive degradation the longer they were buried. Nematodes and fungi pene trated the cuticular layer of mill-damaged seed. Attaching a hammer mi ll or a roller mill to a grain combine to treat cheat seed before it i s returned to the field could provide a novel method of cheat control.