Effect of Rice yellow mottle Sobemovirus on yield in some rice cultivars

Abstract

The impact of Rice yellow mottle virus (RYMV) on rice yield and yield components was studied studied under screenhouse and field conditions The screenhouse experiment was arranged as a completely randomized design with three repetitions while the field experiment was laid out in a randomized complete block design with three replicates. A total of 14 rice cultivars were inoculated with the virus. The effect of RYMV on all the measured parameters was significant both in the screenhouse and under field conditions. The screenhouse results showed that four cultivars (GIGANTE, WAB 189-B38HB, WAB 450-38HB and WAB 450-160HB) were moderately resistant to the virus while the remaining ten (BOUAKE 189, FARO 29, FARO 35, FARO 44, FARO 46, FARO 52, FARO 54, FARO 55, ITA 306 and YARDAS) were moderately susceptible. Plant height ranged from 60.9 (FARO 35) to 108.4 cm (WAB 450-160 HB), number of tillers per plant varied from 4.3 (FARO 46) to 10.2 (BOUAKÉ 189), days to 50 % heading was in the range of 74 (FARO 46 and FARO 55) to 122 (FARO 29) while paddy yield per plant varied from 0.8 (FARO 54) to 2.3 t ha-1 (WAB 450-38HB). However, field experiments indicated that BOUAKE 189, FARO 29, FARO 35, FARO 44, FARO 52, FARO 54, and GIGANTE were moderately resistant to the virus regardless of the location while the rice cultivars WAB 450-160HB was moderately susceptible to the disease at both locations. The rice cultivar FARO 46, FARO 55, WAB 189-B38HB and WAB 450-38HB showed moderate resistance to the pathogen at Bomo alone. On the other hand, ITA 306 and YARDAS rice cultivars exhibited moderate resistance and susceptibility to the virus at Sayen Gobirawa and Bomo, respectively. Plant height, number of tillers per plant, days to 50 % heading and paddy yield ranged from 38.9 (BOUAKE 189) to 67.7 cm (FARO 54), 3.1 (WAB 189-B38HB) to 15.8 (FARO 52), 80 (FARO 46 and FARO 55) to 124 (FARO 29), and 1.4 (FARO 46 and WAB 189-B38HB) to 3.6 t ha-1 (FARO 52), respectively. Plant breeders can take advantage of this information to develop RYMV resistant and high yielding rice cultivars.