Effects of growth conditions on grain molding and phenols in sorghum caryopsis

Received 9 March 1989; Available online 27 July 2009. Phenolic compounds (PC) and phenolic acids (PA) were quantified in mature caryopses of sorghum grown in wet or dry environments. Seventeen cultivars varying in pericarp color and presence of a pigmented testa exhibited different levels of resistance to molding in the wet environment. Sorghum caryopses with a white pericarp contained lower levels of free PC (14μg/caryopsis) than those with a red pericarp (41 μg/caryopsis) when grown in the dry environment. This difference diminished under humid conditions. Cultivars with a pigmented testa were more resistant to grain molding, contained higher levels of free PC (151 μg/caryopsis), and had a softer endosperm texture than cultivars without a pigmented testa. In cultivars without a pigmented testa, higher levels of free PC and free PA, especially free p-coumaric, ferulic, and caffeic acids, were observed in mold-susceptible cultivars. A scatter plot of free PC vs. free p-coumaric acid indicated that mold-susceptibility was related to higher levels of p-coumaric acid, regardless of environment