Preharvest aflatoxin contamination of groundnuts subjected to terminal drought stress in postrainy season.

Groundnuts grown in the postrainy season under terminal drought stress imposed by withholding irrigation, or under a water-deficit gradient created by line-source sprinkler irrigation, were examined for preharvest aflatoxin contamination. High levels of aflatoxin B1 were found in damaged seeds in both situations. When grown under continuous drought-stress, toxin levels in damaged seed samples ranged from 1480 to 2467 [Symbol: see text]g/kg in the 1990/91, and 1.3 to 2000 [Symbol: see text]g/kg in the 1991/92 postrainy seasons. Aflatoxin B1 contamination in all damaged seed samples increased with increasing water deficit; toxin levels ranged from 26 to 850 [Symbol: see text]g/kg across the water deficit gradient. Aflatoxin was either absent or almost negligible (1-2 [Symbol: see text]g/kg) in apparently undamaged seed samples. Low risk of aflatoxin contamination in apparently undamaged seeds of groundnuts grown in postrainy seasons is indicated, even when there is terminal drought stress.