Genetic variations of rice yellow mottle virus disease on selected rice (Oryza sativa L) genotypes and their effects on yield and yield-related traits

Abstract

Rice yellow mottle virus (RYMV) is one of the most important disease affecting rice production in Africa. This research aimed to estimate  the effect of RYMV disease on some yield-related traits in Korean rice germplasm recently introduced into Ghana and identify new  sources of RYMV resistance for use in breeding. One hundred and seventy-six (176) rice genotypes including two highly resistant and a  susceptible check, were used for this research. The experiment was laid in 4 × 44 lattice design with four replications in RYMV inoculated  and non-RYMV inoculated environments in a screen house at CSIR-Crops Research Institute (CRI), Fumesua, Ghana, in 2019. The non- RYMV inoculated environment served as a control. Significant positive correlations were observed between disease severity and  percentage grain yield reduction. RYMV reduced the culm length, tiller number, plant height, panicle number, biomass, and grain yield.  The first five principal components explained 92.39% of the variation in the germplasm, with panicle number, tiller number, heading date,  grain yield/plant and disease severity being the main discriminatory traits. The biplot indicated that genotypes 8261112 and  8261119, together with Gigante and Tog7291 (resistant checks), were the least impacted by the disease. We identified four main clusters  from the hierarchical cluster analysis. Five highly resistant and 10 resistant genotypes were identified. The newly identified resistant  genotypes will be used in breeding for resistance to RYMVdisease in Africa.