Screening for resistance to downy mildew disease Pseudoperonospora cubensis (Berk. and Curt.) Rostov. in Cucumber (Cucumis sativus L.)

Downy mildew, a foliar disease caused by the oomycete Pseudoperonospora cubensis (Berk. and Curt.) Rostov, is one of the most destructive disease of cucumber (Cucumis sativus L.). Moderately resistant cultivars are available, but yield losses are high without the use of fungicides, therefore, higher levels of resistance are required to reduce the use of fungicides. Therefore, in the present study, 12 advance breeding lines along with susceptible check of cucumber were screened against downy mildew disease under natural field condition and artificial inoculation through seedling assay technique. The results confirmed that three lines namely IIHR-177-1-1-S7, IIHR-82-1-S6 and IIHR-81-1-S6 were found to be resistant with <10 per cent disease index (PDI) and significantly outperformed against check var. Swarna Agethi for yield and quality traits. These high yielding resistant lines can be utilized as one of the parents for the development of downy mildew resistant hybrids/ varieties.