Response of 20 Rice Genotypes to the Rice yellow mottle virus (RYMV) under Natural Infection Conditions in the M'bé Valley of Côte d'Ivoire

One of the major constraints on rice production in Africa is the yellow mottle virus (RYMV) disease caused by Rice yellow mottle virus. In the context of the complex nature of this disease and the rapid development of its epidemics, only an integrated approach within a controlled ecological framework can lead to the development of an effective and sustainable control strategy. In order to search for varieties able to resist this virosis, a screening was carried out under natural infection conditions to assess the resistance capacity of 20 rice genotypes, including ten F1 hybrids and ten locally grown varieties. The study was carried out in Bouaké using a split plot system with three replicates. NPK fertilizers (12 24 18) and urea (46% N) were applied at 150 and 100 kg/ha respectively. The incidence, AUSPC and progression rate of RYMV disease were evaluated in the different varieties tested. Serological analysis confirmed the presence of RYMV in the collected leaf samples. The results showed that Palawan (0.13), Wita 9 (0.11), AR051H (0.19) and AR034H (0.09) had the lowest disease progression rates compared to Kpatè (2.3); Soungrouba (1.26); Marigbè (1.26); AR638H (1.56); Kouiklonlé (0.88) and GT11 (0.89) in which the highest rates of disease progression were observed. Similarly, the incidence of RYMV recorded by stage of genotype development was lower in Palawan, Wita 9, AR051H and AR034H. The Palawan, Wita 9, AR051H and AR034H varieties can be deployed without great risk in central Côte d'Ivoire. However, an evaluation under semi-controlled conditions should be considered in order to confirm the behaviours of the different genotypes. These varieties could be exploited pending the large-scale deployment of improved, naturally resistant RYMV genotypes.