Incidence and Distribution of Rice Yellow Mottle Virus Disease in Kebbi State, Nigeria

The study was conducted to assess the incidences of Rice Yellow Mottle Virus disease (RYMVD) in Kebbi State Nigeria, a field survey was conducted in four rice-growing areas of the State. Rice fields were selected randomly at 2 km interval, severity of the disease was assess using arbitrary five-point scale and disease incidence was assessed according to the proportion of the plants showing symptoms. Thirty plants were assessed in each field visited. Symptoms occurred in varying levels of incidence. The presence of RYMV in the collected samples was confirmed using Reverse Transcription Polymerase Chain Reaction (RT-PCR). Mottle/yellowing symptom was found more on the plants assessed (46%) followed by leaf curling (21%), leaf necrosis (09%), leaf deformation (11%) and irregular patches (13%). RYMVD was found highly distributed in the State with average incidence of 54.38%. The highest incidence was recorded in in Yauri (67.50%) followed by Argungu (55.00%), Bagudo (52.50%) and the lowest was recorded in Suru (42.50%). The average symptom severity across all the four Local Governments visited was 2.8, the highest was recorded in Yauri (3.2), followed by Argungu (2.9), Bagudo (2.7) and Suru 2.3. The information obtained in this study would assist rice breeding programs to develop durable RYMV rice resistant cultivars and guide in the identification of RYMVD hot spot locations for seed multiplication trials in Kebbi State.