Screening spring wheat for midge resistance in relation to ferulic acid content

The concentration of ferulic acid TA), the major phenolic acid in the wheat kernel, was found to differ significantly in the mature grain of six wheat cultivars known to have a range of tolerance to the orange wheat blossom m idge (Sitodiplosis mosellana). Differences in FA content were correlated wi th floret infestation level of the cultivars. The wheat cultivars ranked si milarly in FA content at the four locations where they were tested, despite a significant effect of environment. Ferulic acid was synthesized mainly d uring the early stages of grain filling but at different rates among cultiv ars. Ferulic acid was concentrated primarily in the shorts and bran fractio ns in an insoluble-bound form. A high correlation was obtained between FA c ontents as determined by GLC, fluorometry, UV, and colorimetry. The colorim etric procedure was modified as a qualitative, simple, and rapid test for i dentifying midge-resistant wheat and evaluated in several field trials. The method should provide a rapid tool in the preliminary screening of experim ental lines in the development of midge-resistant wheat cultivars.