Browsing by Author "Munganyinka, Esperance"

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    Combining ability for resistance to rice yellow mottle virus disease in interspecific and intraspecific rice Genotypes
    (African Journal of Crop Science, 2015) Munganyinka, Esperance; Edema, Richard; Lamo, Jimmy; Gibson, Paul; Rukundo, Placide
    Estimates of combining ability for resistance to rice yellow mottle virus disease (RYMV) were obtained in the green house of National Crops Resources Research Institute, Uganda. The study involved forty-one F2’s diallel crosses and their five intraspecific and four interspecific parental lines. Effects of both general combining ability (GCA) and specific combining ability (SCA) for RYMV reactions were significant, with a preponderance of GCA effects. Of parental lines used in this study, Naric 1, Nerica 6 and WAC 116 were good combiners for transferring resistance genes to their progenies. In this study, most genotypes with good resistance were good general combiners expect Gigante, that despite its good mean performance, combined badly for resistance to RYMV. The crosses with the best resistance were Naric 1x Gigante, Naric 1x Nerica 6, Nerica 6 x Nerica 4 and Nerica 1 x Nerica 6. From this study, we suggest that selection of parents as donors for resistance should consider both GCA and parental performance. On the basis of predominant additive genetic effects observed in the present study, we believe that combinations of interspecific parents may be used to produce rice varieties resistant to RYMV, and that selection in early selfing generations should be effective.
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    The reaction of intraspecific and interspecific rice cultivars for resistance to rice yellow mottle virus disease
    (European Journal of Experimental Biology, 2016) Munganyinka, Esperance; Edema, Richard; Lamo, Jimmy; Gibson, Paul
    A study was conducted in a green house of National Crop Resource Research Institute, Uganda to determine the reaction for resistance to rice yellow mottle virus (RYMV) in nine rice genotypes. Four were interspecific (N-1, N-4, N-6 and Naric 1) and five intraspecific (two locals K5 and K85, and three introduced WAC 116, WAC117 and Gigante). The screening of these parental materials for resistance to RYMV was done by artificial inoculation with a virulent isolate from Iganga. For among the materials tested, none was found to be immune. The results revealed four patterns of reaction to RYMV among the cultivars: three resistant (WAC 116, WAC 117 and Naric1), four moderately resistant (Nerica 6, Nerica 4, Nerica 1 and Gigante) and two susceptible (K85 and K5). In the current study, Gigante was recorded to have the severity of RYMV symptoms. Furthermore, lines WAC 116, WAC 117 and Naric1 were identified as sources of resistance to RYMV, and therefore candidates for use as parents to improve resistance in susceptible preferred local rice varieties.