Cowpea is the most important legume in the Eastern and Northern region of
Uganda where both its leaves and grains are used as food. Its cultivation in Uganda is constrained by many factors. In
this paper, the authors aimed at screening cowpea genotypes against Fusarium
redolens, a root rot causing pathogen that was found to be the
most devastative to cowpea in greenhouse condition.
In the study, 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 1T, 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.
In addition, field
evaluation studies are recommended as it is essential to evaluate the stability
of this resistance in varying environments especially under severe stresses to
avoid disease escapes.
Article by Roy
Wanjala Namasaka, et al, from Uganda.
Full access: http://mrw.so/RPmeo
Image by MelindaChan
^..^, from Flickr-cc.
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