Screening of resistance to cucumber green mottle mosaic virus in bottle gourd mutated by Ethyl Methane Sulphonate (EMS)

Cucumber green mottle mosaic virus (CGMMV) is a major threat to cucurbits-producing regions worldwide. Conventional breeding process takes much time to cross plants and to select a good variety. In contrast to conventional breeding, mutation breeding accelerates the process of cultivar development and increases variety within a crop species. Hence, the aim of this study was to develop bottle gourd lines that were resistant to CGMMV using Ethyl Methane Sulfonate (EMS) mutagenesis. By treating wild-type seeds (M0) with EMS, bottle gourd lines (M1) were produced. "M1" lines were self-pollinated; as a result, 303 "M2" families were obtained. From M2 families, a total of 2444 "M3" lines were obtained to screen resistance to CGMMV. The "M3" lines were then classified into 5 levels based on the development of symptoms 11–30 days post-inoculation, with very light symptoms 13.91%, light symptoms 34.0%, mild symptoms 33.71%, severe symptoms 4.62%, and death lines 4.62%, respectively. About 278 (11.38%) "M3" lines in glasshouse experiments showed no symptoms at 30 dpi. Using a double-antibody sandwich enzyme-linked immunosorbent assay at 60 dpi, 44 "M3" lines out of 278 were determined to be asymptomatic and negative for CGMMV. These lines were then transplanted in the field. Four of the 44 "M3" lines were asymptomatic in the field and tested negative for CGMMV using the DAS-ELISA. The new findings show that using EMS-induced mutations to create novel CGMMV highly resistant bottle gourd cultivars could be a viable option.