Determining the susceptibility of different basil varieties to downy mildew caused by Peronospora belbahrii. Plant Pathol Microbiol

Abstract

Field experiments were carried out under natural infection of basil downy mildew in the Experimental Farm of Sids Agricultural Research Station, Agricultural Research Center, Beni-Sweif governorate in 2016 and 2017 for screening a number of local varieties of basil and French basil grown in Beni-Sweif governorate, Egypt for susceptibility to basil downy mildew. Generally, all varieties tested varied in their response to downy mildew infection. The five basil varieties tested were divided into five groups based on the resistance reaction screened under field condition into: resistant variety (Lv 1), moderately resistant (Lv 2), moderately susceptible (Lv 3), susceptible (French basil) and highly susceptible (Lv 4) and classified to three chemotypes due to their content of the dominant component as follows, methyl cinnamate chemotypes (Lv 1 and Lv 3), linalool chemotypes (Lv 4 and French basil cultivar) and methyl chavicol chemotype (Lv 2). However, phenols, peroxidase and polyphenol oxidase activities were found higher in resistant varieties as compared to susceptible varieties.