Evaluation of Cowpea Genotypes for Resistance to Fusarium redolens in Uganda
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
American Journal of Plant Sciences
Abstract
Fusarium redolens, a virulent fungus which causes damping off, leaf yellowing,
wilting and root rots has recently been devastating cowpea fields in
Uganda. This study aimed at identifying cowpea genotypes that are resistant
to Fusarium redolens. Therefore, ninety cowpea genotypes were evaluated two
times against a highly virulent Fusarium redolens (isolate from Zombo in
Paidha district) in the screen house in 2016. Genotype effect was highly significant
(P < 0.001) for root rot severity. Based on the Index of Susceptibility
(IS), three genotypes (Asontem, Dan1 LA and IT89KD-88) remained resistant
(IS < 3.5) over the two screening periods, 72 moderately resistant (3.5 ≤ IS <
6.5) and 11 susceptible (IS ≥ 6.5). Resistance was found to be enhanced by
presence of lateral roots above or at the ground level. Further results suggested
a difference in genetic control of resistance to root rots and seed rots
caused by Fusarium redolens . All the released varieties tested (SECOW 1 T,
SECOW 2 W, SECOW 3 B, SECOW 4 W and SECOW 5 T) had moderate resistance
to Fusarium redolens . Correlation analysis revealed root rot severity
was strongly correlated to disease incidence (+0.64, P < 0.001), to proportion
of plants with lateral roots (−0.56, P < 0.001), to amount of leaf chlorophyll
(−0.53, P < 0.001) and to proportion of plants that died prematurely due to
Fusarium redolens infection (+0.45, P < 0.001). No significant correlation was
detected between root rot severity and proportion of plants that germinated.
The established resistance could be exploited for improvement of farmer preferred
cowpea varieties towards Fusarium redolens resistance in Uganda.
Description
Keywords
Root Rot Severity, Lateral Roots, Seed Rots, Root Rots, Resistance, Index of Susceptibility
Citation
Namasaka, R.W., Tusiime, G., Orawu, M., Gibson, P., Nyiramugisha, J. and Edema, R. (2017) Evaluation of Cowpea Genotypes for Resistance to Fusarium redolens in Uganda. American Journal of Plant Sciences , 8, 2296- 2314. https://doi.org/10.4236/ajps.2017.89154