REACTION OF CULTIVATED CEREALS TO CLAVICEPS PURPUREA

Abstract

The influence of inoculum concentration on the reaction induced in species and cultivars of commercial cereals by two isolates of ergot (Claviceps purpurea (Fr.) Tul.) was investigated. Differences were observed among and within species with respect to each of the three components of the disease reaction, i.e., frequency of sclerotia, size of sclerotia, and amount of honeydew produced. Spring wheat (Triticum aestivum L.) was less susceptible than the other cereal species. Significantly fewer sclerotia were produced on spring wheat except at high and low inoculum concentrations and the sclerotia were smaller and the honeydew less abundant. Inoculation of selected cultivars within each of the cereal species showed that only cultivars of spring wheat and durum wheat (T. durum Desf.) differed in the expression of the disease reaction. The spring wheat cultivar Kenya Farmer, and durum wheat cultivar Carleton were less susceptible than the commercial cultivars. Inoculum concentration affected sclerotial frequency in the species and cultivars tested but did not affect sclerotial size and honeydew development. The two isolates used in this study differed in their ability to induce sclerotia and also affected sclerotia size and honeydew production.