EVALUATION OF A COLLECTION OF RICE LANDRACES FROM BURKINA FASO FOR RESISTANCE OR TOLERANCE TO RICE YELLOW MOTTLE VIRUS
H. Kam, M.D. Laing, Y. Séré, D. Thiémélé, A. Ghesquière, N. Ahmadi, M.-N. Ndjiondjop
A collection of accessions of Burkina Faso rice germplasm was evaluated for resistance using four Rice yellow mottle virus (RYMV) isolates: Ng122, Ng144, B27 and BF1. B27, an isolate from Benin was used first, followed by Ng122 and Ng144 (isolates from Niger), and BF1 an aggressive isolate from Burkina Faso was used last to assess the accessions status against RYMV. Fourteen-day-old plantlets were inoculated and symptoms scored fortnightly from 14 to 56 days post inoculation (dpi). Plant height of all accessions was recorded at 49 dpi with isolates Ng122 and Ng144. The Oryza sativa accessions of the collection were highly susceptible except one (BM24), which combined partial resistance and tolerance. Twenty one O. glaberrima accessions out of 48 were found resistant to Ng122 and Ng144. When these 21 accessions were subsequently screened with the aggressive RYMV strain BF1, eight of them displayed a delay in the appearance of RYMV symptoms while two showed resistance. The new sources of resistance identified in this study, could be exploited in breeding to control the spread of RYMV in Africa.