Amitrole (3-amino-s-triazole), dichlormate (3,4-dichlorobenzyl methylcarbamate), and pyriclor (2,3,5-trichloro-4-pyridinol) inhibited normal carotenogenesis in etiolated wheat (Triticum aestivum L. var. Coker 65-20) seedlings. Carotenoid precursors accumulated in treated plants. In