Evaluation of the susceptibility of eggplant cultivars to infection with the fungus Sclerotinia sclerotiorum (lib.) deBary causing white stem rot disease in laboratory and greenhouse conditions

Abstract

This research was conducted at the College of Agriculture /Baghdad University during 2012 - 2013.The aims of this project  were  to evaluate three eggplant cultivars( Thurayya F1, Barshalona and Paris)for their resistance to Sclerotinia sclerotiorum (lib.) deBary in laboratory and greenhouse, In addition to develop a low-cost and high efficiency inoculation methods that can generate consistent results for screening the plants for resistance to  sclerotinia stem rot . Three methods  of inoculation were  applied: the apical meristemes using plants of one month growth stage , inoculated with PDA mycelial  pathogen plugs (5mm), detached leaf assay with PDA mycelial  plugs (5mm) of pathogen  and Oxalic acid (10mM). Lesion length , percentage of infected leaf area and peroxidase activity were measured .The results shown  symptoms developed within 1 and 8 dayse after inoculation with both detached leaf assay and Oxalic acid   and apical meristemes treatments respectively. Significant differences (P≤1%) among eggplant  cultivars resistance  to S. sclerotiorum were found. Thurayya F1 was the less sensitive to infection when produced lesion of 14.67mm in length  and 0.6 % percentage of infected leaf area. Whereas, Barshalona  and Paris produced 45 , 93.67 mm, and 1.39% , 1.79% respectively. Peroxidase activity estimated in the detached leaves infected was three and five times more fold in Thurayya F1 and Barshalona cultivar respectively  compared to control, while no significant differences occurred in Paris cultivar