Resistance to Rice yellow mottle virus in rice germplasm in Madagascar

Abstract

Salaudeen M.T. (2014): Relative resistance to Rice yellow mottle virus in rice. Plant Protect. Sci., 50: 1-7. We identified sources of Rice yellow mottle virus (RYMV) resistance in rice cultivars. Eight cultivars together with susceptible and resistant controls were evaluated under screenhouse conditions as inoculated and uninoculated treatment in completely randomised design with three replications. Seedlings were inoculated with the virus by sap transmission at two weeks after sowing. Disease incidence and severity (scale 1-9: 1-3 = green leaves with sparse dots or streaks, 9 = yellow or orange leaves and some plant dead), yield, and agronomic traits were recorded. Data analyses included Area Under the Disease Progress Curve (AUDPC), independent t-test, and Analysis of Variance. According to differences in most measured traits control cultivars FARO 29 and Gigante were proved to be the most susceptible and partially tolerant ones, respectively. Cvs FARO 12, FARO 17, FARO 37, and FARO 52 were classified as partially tolerant. Uninoculated control plants performed better than the inoculated for all the yield and agronomic parameters. Reduction in plant height (6%) and number of tillers per plant (4.8%), increased days to heading (3 days), and reduction in paddy yield (6.5%) was lowest in cv. Gigante. Paddy yield per plant of the RYMV-inoculated was the highest in cv. Gigante (2.4 g). The rice cultivars which combined RYMV-resistance with high-yield could be utilised in rice breeding programmes in order to enhance food security.

Relative resistance to Rice yellow mottle virus in rice

“…The highly susceptible reactions of cvs FARO 29 and FARO 44 concur with the previous investigation reported by Abo et al (2002). The partially tolerant cultivars performed better than the susceptible ones because of their strong genetic background to limit the deleterious impacts of the virus (Rakotomalala et al 2008). Earlier, N'Guessan et al (2001 encountered high genetic resistance to RYMV in cv.…”

Farmers’ Perception and Impact of Rice Yellow Mottle Disease on Rice Yields in Burkina Faso

“…Most cultivated rice varieties have been reported as highly susceptible [14]. Attempts to control rice yellow mottle disease have been mainly directed to breeding for resistance to RYMV [15].…”

“…Attempts to control rice yellow mottle disease have been mainly directed to breeding for resistance to RYMV [15]. A few sources of resistance to be used in breeding programs were identified [14]- [17]. However, the durability of such resistance was questioned, as resistance-breaking isolates of the virus were shown to occur frequently [18] [19].…”

Evaluation of rice cultivars for resistance to rice yellow mottle virus

“…Rymv1-2 has only been detected in Gigante and Bekarosaka, which are two cultivars of Asian rice var. indica (Ndjiondjop et al, 2001;Rakotomalala et al, 2008). RYMV2 was recently found in the African rice cultivar Tog7291 (Thiémélé et al, 2010).…”

“…These two rice species are affected by Rice yellow mottle virus (RYMV) disease, which is only found on this continent (Kouassi et al, 2005). The screening of cultivars belonging to both cultivated species, by several authors identified two major genes of resistance: RYMV1 and RYMV2, which provide high levels of resistance (Fomba 1988;Ndjiondjop et al, 1999;Rakotomalala et al, 2008;Thiémélé et al, 2010). High resistance is characterised by symptomless plants and the blockage of virus movement inside the plant (Ndjiondjop et al, 2001).…”