Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 50: 3501 - 3511. Published February 27, 2012.
Diagnosis and importance of rice yellow mottle disease epidemics in Niger republic
Issaka S.1, 2, 3, Basso A.1, 2, Sorho F.3, Onasanya A.4, Haougui A.1, Sido A.Y.1, Aké S.3, Fargette D.5 and Séré Y2*.
1 National Institute for Agronomic research of Niger (INRAN), BP. 60 Kollo (Niger),
2 Pathology Unit of Africa rice center, 01 Bp. 2031 Cotonou (Bénin),
3 University of Cocody-Abidjan, 22 BP. 582 Abidjan 22 (Côte d’ivoire)
4 Plant Pathology Unit, Africa Rice Center (AfricaRice), P.O. Box 33581, Dares-Salaam, Tanzania
5 IRD, BP6450, 34394 Montpellier Cedex5 (France)
*Correspondence author: Y. Séré, Tel: +229 21 35 01 88 Fax: +229 21 35 05 56. E-mail: y.sere@cgiar.org
ABSTRACT
Objectives: To diagnosis Rice Yellow Mottle Virus (RYMV) disease and evaluate its importance (geographical distribution, incidence, yields losses and virus population structure) in Niger Republic.
Methodology and Results: A phytosanitary survey of all irrigated perimeters indicated that Rice Yellow Mottle Virus was present in most rice fields of Niger Republic with an average incidence of 5 to 90 %. In some fields, the incidence was very high (60 to 90 %) but in others, it was less than 30 %. The yield losses calculated in 4 rice sites under severe attack were between 35 and 71 %. The pre-characterization of isolates collected during the survey revealed diversity at both serological and pathological levels, and most importantly a significant proportion of resistance breaking (RB) isolates. A study on (Poacea and Cyperaceous) suggested that the species Laersia hexandra, Paspalum emplectens, Echinochloa colona, Panicum repens, Cynodon dactylon, Cyperus rotondus, Kylinga sp. and Cyperus sp. were hosts reservoirs of Rice Yellow Mottle Virus in Niger environment. Their role in disease propagation was discussed.
Conclusion and application: These results reporting the importance of the disease and the presence of RB isolates make necessary complementary studies with a large set of Niger-RYMV isolates and varieties.
Key words: Niger-RYMV, disease incidence, yields losses, hosts reservoirs, Resistance breaking isolates.
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