The RAPD primers S111, S119, S1117, S1109, S1103, S109 and S105 were found to be better indicators of molecular diversity among isolates than JEL primers. The diversity analysis grouped 14 isolates into three major clusters based on disease reaction wherein isolate no. 8 was found the most divergent as well as highly virulent. The remaining isolates were classified into two distinct groups. The importance check details of the study in the context of transfer of resistance gene(s) in the local cultivars specifically

for tropical island conditions is presented and discussed. “
“Bacterial spot, caused by Xanthomonas spp., is one of the major diseases of pepper in Brazil, causing considerable losses to crop productivity. The efficient management of the disease is hampered by the high variability of the causal

agents. In Brazil, there is no knowledge of which species of Xanthomonas occurs on pepper. In this study, 59 strains of Xanthomonas spp. isolated from different selleck screening library pepper-producing regions of Brazil were characterized by biochemical and molecular techniques. Results showed the prevalence of X. euvesicatoria as the causal agent of bacterial spot on pepper in Brazil. “
“Six essential oils were evaluated as to their efficiency in controlling powdery mildew (PM) of flax when they were applied as foliar sprays in an outdoor pot experiment. Onion, flax and fenugreek oils did not affect PM severity ratings – that is, they were ineffective in controlling the disease. On the other hand, black cumin, jojoba and coriander

oil showed variable levels of efficiency in controlling the disease. Black cumin was moderately effective in controlling the disease because it reduced disease severity by 32.87%, while jojoba and coriander oils were highly effective as they reduced disease severity by 66.24 and 68.64%, respectively. Essential oils did not affect seed weight; however, coriander oil was a notable exception as it reduced seed weight by 55%. Straw weight was not affected by any oil. Foliar application of essential oils resulted in significant changes in the levels of protein, phenols, ascorbic acid and malondialdehyde and in activities MCE of peroxidase and polyphenol oxidase. The lack of significant correlation between levels and activities of these biochemical components and PM severity demonstrate that these components are not involved in the suppression of PM by essential oils. Therefore, direct toxicity of essential oils to the causal pathogen Oidium lini is the most likely explanation for the disease suppression. “
“The genetic structure of Puccinia graminis f.sp. tritici isolates sampled in three different regions of Ethiopia in 2006 and 2007 was investigated using 20 SSRs assuming sexual as well as asexual reproduction. Assays showed a high level of genetic diversity within P. graminis f.sp. tritici populations in Ethiopia in both modes of reproductions.