scholarly journals Variation among Tanzania Rice Germplasm Collections Based on Agronomic Traits and Resistance to Rice Yellow Mottle Virus

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 391
Author(s):  
William Titus Suvi ◽  
Hussein Shimelis ◽  
Mark Laing ◽  
Isack Mathew ◽  
Admire I. T. Shayanowako

Rice (Oryza species) is a commercial crop worldwide. Across Africa, the potential yield and quality of rice is diminished by a lack of high performance, locally adapted varieties, and the impact of rice yellow mottle virus (RYMV). The objective of this study was to assess the performance of a diverse collection of rice germplasm for RYMV resistance and agronomic traits, and to select promising lines for breeding for Tanzanian conditions. Fifty-four rice genotypes were field evaluated in two important rice production sites (Ifakara and Mkindo) in Tanzania, which are recognized as RYMV hotspots, using a 6 × 9 alpha lattice design with two replications. There was significant (p < 0.05) genotypic variation for agronomic traits and RYMV susceptibility in the tested germplasm. Seven genotypes with moderate to high RYMV resistance were identified, including Salama M-57, SSD1, IRAT 256, Salama M-55, Mwangaza, Lunyuki, and Salama M-19, which were identified as new sources of resistance genes. Positive and significant correlations were detected between grain yield and number of panicles per plant (NPP), panicle length (PL), number of grains per panicle (NGP), percentage-filled grains (PFG), and thousand-grain weight (TGW), which are useful traits for simultaneous selection for rice yield improvement. A principal component analysis allocated five principal components, accounting for 79.88% of the total variation present in the assessed germplasm collection. Traits that contributed most to variability included NPP, number of tillers/plant (NT), PL, grain yield (GY), and days to 50% flowering (DFL). The genotypes Rangimbili, Gigante, and SARO possess complementary agronomic traits and RYMV resistance, and can be recommended for further evaluation, genetic analysis, and breeding.

Plant Disease ◽  
2001 ◽  
Vol 85 (1) ◽  
pp. 59-64 ◽  
Author(s):  
P. N'Guessan ◽  
A. Pinel ◽  
A. A. Sy ◽  
A. Ghesquière ◽  
D. Fargette

In Côte d'Ivoire, the S2 strain of Rice yellow mottle virus (RYMV) predominated in the forested zones, including the “rice belt” to the west, in each of the cropping systems where rice was grown. The S1 strain occurred more frequently in the northern Guinean savanna, and only S1 isolates were found further north in the Sahelo-Soudanian zones. In mixed infection, S2 dominated over S1 both in viral capsid and RNA contents under temperature regimes encompassing those observed in savanna and forested zones of Côte d'Ivoire. There was no evidence of interactions in virus accumulation between the West African strains S1 or S2 with the more distantly related East African strain S4. Field trials emphasized the impact of RYMV, which induced yield losses of 40 to 60% in several widely grown cultivars of Oryza sativa indica and O. sativa japonica. We report the high resistance of the O. indica cv. Gigante under field conditions which was apparent with all the S1 and S2 isolates tested. Responses to RYMV infection of several cultivars were isolate dependent. With most differential cultivars, responses were not strain specific, with the exception of the O. japonica cv. Idsa6, in which the S2 isolates always induced higher yield losses than the S1 isolates.


2008 ◽  
Vol 122 (2) ◽  
pp. 277-286 ◽  
Author(s):  
M. Rakotomalala ◽  
A. Pinel-Galzi ◽  
L. Albar ◽  
A. Ghesquière ◽  
Y. Rabenantoandro ◽  
...  

2015 ◽  
Vol 40 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Mounirou Sow ◽  
Marie-Noelle Ndjiondjop ◽  
Ibnou Dieng ◽  
Honore Kam ◽  
Olufisayo Kolade ◽  
...  

2014 ◽  
Vol 50 (No. 1) ◽  
pp. 1-8 ◽  
Author(s):  
M.T. Salaudeen

We identified sources of&nbsp;Rice yellow mottle virus&nbsp;(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&ndash;9: 1&ndash;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&nbsp;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.


1970 ◽  
Vol 3 ◽  
pp. 28-34
Author(s):  
Ejigu Ejara, Wassu Mohammed, Berhanu Amsalu ◽  
Zinash Misgana, Mulatu Gabisa, Ganane Tasama

Common bean is among the major crops grown in southern Ethiopia including Borana zone where the majority of the farmers are Agro-pastoralist and produce the crop mainly for home consumption. The area has potential to the production of common bean for food and nutrition security as well as export commodity. However, scarcity of varieties that fit to the environment is one of the major constraints of production. Therefore, this experiment was conducted to evaluate 36 common bean genotypes including seven released varieties to evaluate performance of genotypes for yield and agronomic traits. The field experiment was conducted in 2015 at two locations (Abaya and Yabello) and genotypes were planted in triple lattice design. Data were collected on yield and important agronomic traits. Analysis of variance computed for individual locations and combined analysis over locations revealed significant variations among genotypes for all traits. Moreover, 16.67% of the genotypes had mean grain yield greater than the best performing released variety across locations and the genotypes showed a grain yield as high as 3.25 tons ha-1. Based on results of this study it is recommended to test the high yielding and early maturing genotypes at many locations to develop preferred varieties across many locations.


2010 ◽  
Vol 61 (3) ◽  
pp. 371-382 ◽  
Author(s):  
Séverine Lacombe ◽  
Martine Bangratz ◽  
Florence Vignols ◽  
Christophe Brugidou

2003 ◽  
Vol 148 (9) ◽  
pp. 1721-1733 ◽  
Author(s):  
A. Pinel ◽  
Z. Abubakar ◽  
O. Traor� ◽  
G. Konat� ◽  
D. Fargette

Virology ◽  
1995 ◽  
Vol 206 (1) ◽  
pp. 108-115 ◽  
Author(s):  
C. Brugidou ◽  
C. Holt ◽  
M. Ngon A Yassi ◽  
S. Zhang ◽  
R. Beachy ◽  
...  

Plant Disease ◽  
1999 ◽  
Vol 83 (10) ◽  
pp. 931-935 ◽  
Author(s):  
M. N. Ndjiondjop ◽  
L. Albar ◽  
D. Fargette ◽  
C. Fauquet ◽  
A. Ghesquière

Three cultivars of Oryza sativa (IR64, Azucena, and Gigante) and four cultivars of O. glaberrima (Tog5681, Tog5673, CG14, and SG329) were evaluated for their resistance to two isolates of rice yellow mottle virus (RYMV) by enzyme-linked immunosorbent assay (ELISA) and symptomatology. Cultivars Tog5681 and Gigante were highly resistant, and no symptoms were observed when either virus isolate was inoculated at 10 or 20 days postgermination and assayed by ELISA at 7, 14, 22, 35, 50, or 64 days postinoculation. Azucena showed a partial resistance, whereas the other cultivars were susceptible. Symptom appearance was associated with increase in ELISA absorbance in the systemically infected leaves. The best discrimination among the cultivars occurred when the plants were inoculated at 10 days postgermination. Crosses were made between the highly resistant (Gigante and Tog5681) and the susceptible (IR64) cultivars to determine the genetic basis of resistance to RYMV. Evaluation of F1 hybrids and interspecific progenies, as well as the segregation of resistance in F2 and F3 lines of the IR64 × Gigante cross, provided results consistent with the presence of a single recessive resistance gene common to Tog5681 and Gigante.


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