Evaluation Of Watermelon Germplasm And Advance Breeding Lines Against Powdery Mildew Race '2f'

Podosparea xanthii is the most frequently reported powdery mildew pathogen of watermelon (Citrullus lanatus L.). The utilization of genetic resources for disease resistance is economically and environmentally safer than the use of fungicides. This study was aimed to screen 107 available germplasm and advance breeding lines of watermelon against race 2F of powdery mildew. The melon differential lines were utilized to confirm the powdery mildew race in spring and autumn growing seasons. Here, we have reported some highly resistant cultigens including M16, M11 and M49 with lowest mean severity ratings of 0.58, 1.0 and 1.13, respectively. The mean severity ratings for sensitive cultigens were recorded the highest in ZXG1996 (6.24) and M01 (5.7) on the basis of polyhouse screening and controlled condition screening retest. Moreover, our study suggested that powdery mildew screening for watermelon in the polyhouse at seedling stage could be a good screening method to identify the response against race 2F of powdery mildew. The screening methods and disease assessments were verified in retest of cultigens in controlled environment condition. A significant positive correlation was recorded for mean disease severity rating and percentage disease index between polyhouse screening and controlled condition screening. The identified sources can be utilized for resistance mechanism studies and resistance breeding.