Evaluation of Cowpea Genotypes for Resistance to Fusarium redolens in Uganda

摘要

style="font-family:Verdana;"> style="font-family:Verdana;">Fusarium redolens style="font-family:Verdana;"> style="font-family:Verdana;">, style="font-family:Verdana;">a style="font-family:""> style="font-family:Verdana;">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 style="font-family:Verdana;"> style="font-family:Verdana;">Fusarium redolens style="font-family:Verdana;"> style="font-family:Verdana;">. style="font-family:Verdana;"> Therefore, ninety cowpea genotypes were evaluated two times against a highly virulent style="font-family:Verdana;"> style="font-family:Verdana;">Fusarium redolens style="font-family:Verdana;"> style="font-family:Verdana;">(isolate from Zombo in Paidha district) in the screen house in 2016. Genotype style="font-family:""> style="font-family:Verdana;">effect was highly significant (P style="font-family:""> style="font-family:Verdana;">/span> style="font-family:""> style="font-family:Verdana;">0.001) for root rot severity. Based on the Index of Susceptibility (IS), three genotypes (Asontem, Dan1 style="font-family:""> style="font-family:Verdana;">LA and IT89KD-88) remained resistant style="font-family:""> style="font-family:Verdana;">(IS style="font-family:""> style="font-family:Verdana;">/span> style="font-family:""> style="font-family:Verdana;">3.5) over the two screening periods, 72 moderately resistant (3.5 style="font-family:""> style="font-family:Verdana;">≤ style="font-family:""> style="font-family:Verdana;">IS style="font-family:""> style="font-family:Verdana;">/span> style="font-family:""> style="font-family:Verdana;">6.5) and 11 susceptible (IS style="font-family:""> style="font-family:Verdana;">≥ style="font-family:""> style="font-family:Verdana;">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 style="font-family:Verdana;"> style="font-family:Verdana;">Fusarium redolens style="font-family:Verdana;"> style="font-family:Verdana;">. All the released varieties tested (SECOW 1 style="font-family:""> style="font-family:Verdana;">T, SECOW 2 style="font-family:""> style="font-family:Verdana;">W, SECOW 3 style="font-family:""> style="font-family:Verdana;">B, SECOW 4 style="font-family:""> style="font-family:Verdana;">W and SECOW 5 style="font-family:""> style="font-family:Verdana;">T) had moderate resistance to style="font-family:Verdana;"> style="font-family:Verdana;">Fusarium redolens style="font-family:Verdana;"> style="font-family:Verdana;">. Correlation analysis revealed root rot severity was strongly correlated to disease incidence (+0.64, P style="font-family:""> style="font-family:Verdana;">/span> style="font-family:""> style="font-family:Verdana;">0.001), to proportion of plants with lateral roots ( style="font-family:Verdana;">- style="font-family:Verdana;">0.56, P