Assessment of yield losses due to rice yellow mottle virus under field conditions in burkina faso

Author: 
SEREME Drissa, OUEDRAOGO Ibrahima, WONNI Issa, YAO Nasser, NEYA Bouma James and KONATE Gnissa

Rice yellow mottle virus (RYMV) is one of the most devastating plant viruses and belongs to the Genus Sobemovirus. In West and Central Africa, three RYMV strains (S1, S2 and S3) have been identified based on their molecular typing (coat protein sequences). In 2013, and 2014, a field experiment was conducted, under rainfed lowland conditions in order to evaluate the effect of RYMV on yield and yield components of resistant, tolerant, susceptible and popular cultivars. Yield components and agronomic parameters were evaluated in relation with grain yield and disease severity. In each experiment, ELISA was performed to confirm symptomatic observation. Based on disease rating scale of RYMV, mean incidence and severity of disease were higher in 2013 than in 2014. Except for the 1000-grain weight, all agronomic parameters considered in this study differed significantly between potential and disease-affected conditions (P ≤ 0.01). Experiments on the effect of the virus on yield indicated that mean losses of 33.23% occurred due to RYMV infection. The degree of negative effects as measured by grain yield loss (GYL) varied widely between genotypes, ranging from 0.64% to 51.28%. RYMV-susceptible genotype IR64 was the most affected by RYMV infection (51.28% GYL) followed by the two popular genotypes FKR19 and TS2 with 30.09 and 36.91% GYL respectively. The resistant genotype Gigante recorded 0.64% GYL and while the tolerant genotype showed 21.38% GYL. Our results confirmed the importance of RYMV in rice production and emphasize the need to control the disease. Furthermore, more research is needed to elucidate the role of RYMV in yield loss for current and newly released rice cultivars. The outcome of the study could be used as guidance for further display of rice genotypes in West Africa.

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