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Prevalence des principales maladies sur des varietes de riz cultivees dans le departement de l’alibori au Nord-Benin
Abstract
Fields surveys were conducted in 21 rice growing sites of Gogounou, Kandi, Banikoara and Malanville in Northern Benin (Alibori) in 2006 growing season in order to identify rice diseases in that area.
Identification of diseases was based on field symptoms as well as on microscopic observations in the laboratory, and on immunological (ACP-ELISA) tests for viral diseases. Disease severity was assessed
with a 10 scaled severity class, and the Chi square test was used to test the susceptibility of cultivated varieties to the identified diseases.
Over 15 rice varieties were found to be cultivated in Alibori Department with their relative importance (in percent) as follows: « Tous venants » (32,9%), Adny11 (17,9%), Beris21 (13,2%) and INARIS88 (11%).
Some less represented varieties like Gambiaka, IR8, Wita4 and V24 were only encountered in some localities. The rice diseases identified in Alibori were rice brown leaf spots, rice blast, rice yellow mottle virus
(RYMV) and false smut. Rice brown leaf spots and rice blast were found in all localities and their incidence varied from 13 to 28% for rice brown leaf spots, and from 16 to 29% for rice blast. False smut and RYMV were only found in the irrigated perimeter in Malanville and their prevalence were respectively over 4% and 15%.Disease susceptibility of the cultivated varieties varied greatly. Gambiaka, Inaris 88, « Tous venants » and Adny 11 appeared more susceptible to rice brown leaf spots, as compared to Beris 21, Irat127, V4 and the Nericas. The susceptibility of the varieties to rice blast, in increasing order, appeared as: Irat127information on varieties that could be considered in a standard screening programme.
Identification of diseases was based on field symptoms as well as on microscopic observations in the laboratory, and on immunological (ACP-ELISA) tests for viral diseases. Disease severity was assessed
with a 10 scaled severity class, and the Chi square test was used to test the susceptibility of cultivated varieties to the identified diseases.
Over 15 rice varieties were found to be cultivated in Alibori Department with their relative importance (in percent) as follows: « Tous venants » (32,9%), Adny11 (17,9%), Beris21 (13,2%) and INARIS88 (11%).
Some less represented varieties like Gambiaka, IR8, Wita4 and V24 were only encountered in some localities. The rice diseases identified in Alibori were rice brown leaf spots, rice blast, rice yellow mottle virus
(RYMV) and false smut. Rice brown leaf spots and rice blast were found in all localities and their incidence varied from 13 to 28% for rice brown leaf spots, and from 16 to 29% for rice blast. False smut and RYMV were only found in the irrigated perimeter in Malanville and their prevalence were respectively over 4% and 15%.Disease susceptibility of the cultivated varieties varied greatly. Gambiaka, Inaris 88, « Tous venants » and Adny 11 appeared more susceptible to rice brown leaf spots, as compared to Beris 21, Irat127, V4 and the Nericas. The susceptibility of the varieties to rice blast, in increasing order, appeared as: Irat127information on varieties that could be considered in a standard screening programme.
