Resistance of Hibiscus esculentus L. and Vigna sinensis (L.) Endl. to Pseudocercospora and plant peroxidase activity in relation to infection

Five cultivars of Hibiscus esculentus L. and six cultivars of Vigna sinensis (L.) Endl. were tested for their relative resistance to Pseudocercospora spp. Differences in susceptibility to the leaf spot pathogen were observed in both host and non-host interactions. The H. esculentus cv. South Sea and V. sinensis cv. Purple Mart were most susceptible to Pseudocercospora abelmoschi and P. cruenta, respectively. The H. esculentus cv. Pure Luck was most tolerant to P. abelmoschi while the V. sinensis cv. KY Bush was highly resistant to P. cruenta. A distinct host-specific interaction was observed among the different species of Pseudocercospora. Cultivar specific interactions were most pronounced between V. sinensis and P. cruenta. A direct correlation was observed between the variation in peroxidase activity in the soluble fraction of inoculated leaves and resistance to infection in H. esculentus and V. sinensis cultivars. The soluble fraction of inoculated leaves had higher peroxidase activity than either mitochondrial or chloroplast extracts.