The concentration of phenolic compounds in the silks of five maize inbred lines ('CO272', 'F7', 'F2', 'A641', and 'CO266') of varying susceptibility to Fusarium graminearum was determined at three stages of silk development. The level of phenolic compounds in noninoculated silk tissue increased with silk development for only two of the inbreds. A suspension of F. graminearum spores was sprayed on the exposed silk of the same inbreds. Silk tissue collected from the silk channel 1 to 14 days after this inoculation was analyzed for phenolic compounds. The level of phenolic compounds increased relative to a water control in the most resistant line 'CO272' and decreased relative to water controls in susceptible lines. From thin layer chromatography of the phenolic extracts, flavones were the major phenolic compounds present. Five flavones were identified using high performance liquid chromatography: iso-orientin, iso-vitexin, maysin, luteolin, and apigenin. Key words: maize, corn, Fusarium graminearum, silk, phenolic, flavone.
Thirty-seven maize inbreds and a diallel cross of 12 inbreds selected from the 37 were evaluated at each of two locations for resistance to Fusarium graminearum ear rot infection via the silk and/or silk channel. Artificial inoculation was accomplished with a spore suspension injected into the silk channel of individual ears. Mean disease ratings, made on a scale of 1–7, revealed that most of the 37 inbreds were susceptible. Twelve of the inbreds, chosen to represent a range of susceptibility, were intercrossed in a complete diallel arrangement. Disease incidence and severity in the parents, crosses and reciprocals were evaluated in two environments. Genotype, general combining ability (GCA), and specific combining ability (SCA) effects were significant for both mean disease rating and disease incidence data. The GCA effects of the parents were correlated both to mean disease ratings and to disease incidence, with the most resistant parent, CO272, having the largest negative GCA. The performance of all hybrids could not be predicted simply on the basis of the performance or GCA of the parents. Reciprocal differences for mean disease ratings were significant in one environment. Four inbreds were identified as having significant GCA for resistance to F. graminearum infection via the silk.Key words: Maize, corn, diallel, resistance, Fusarium graminearum, silk
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.