Characterization and Detection of Yellow Vein Disease of Okra (<em>Abelmoschus esculentus</em> (L.) Moench) in Sri Lanka

Abstract

Begamoviruses transmitted by whitefly (Bemisia tabaci Genn, Family Aleyrodidae) cause severe damage to crop plants showing varying symptoms in different crop species. Okra Yellow Vein Mosaic Virus (OYVMV) is one of the most devastating diseases reported in okra cultivation worldwide. In this study, OYVMV disease severity and incidence of three recommended okra varieties were evaluated in field conditions at three different locations; Gannoruwa, Mahailuppalama and Angunakolapalasse. Similar disease symptoms were observed in Mahailuppallama and Angunakolapalasse. In Gannoruwa late infection caused lesser disease incidence and severity. Statistical analysis showed significant difference in severity and incidence of OYVMV among varieties as well as locations. MI 7 and MI 5 showed significantly high disease severity than Haritha while location Mahailluppallama showed significantly high disease severity followed by Angunakolapalasse. Diseased samples collected from these three locations and two additional locations i.e. Kilinochchi and Vauniya were subjected to PCR amplification with different begamovirus specific primers to identify the cross infection with other begamovirus diseases. All symptomatic samples collected from different locations showed positive results for OYVMV specific primer while none of the diseased samples showed positive results for Chili leaf curl virus, Tomato leaf curl virus, Okra leaf curl virus and Okra leaf curl crinkle virus disease specific primers. This study revealed that there is location and variety effect on OYVMV disease incidence and in these locations tested okra varieties were not cross infected with other tested viruses. Sequence analysis has to be done to identify genetic diversity of okra YVMV in different locations.

Keywords

• disease incidence, disease severity, okra yellow vein mosaic virus