Relative resistance of six cowpea cultivars as affected by the concomitance of two nematodes and a fungus

T. A. Khan, S. I. Husain

Abstract


Cowpea cultivars that were resistant or moderately resistant against individual pathogens lost their resistance in the presence of the other pathogens except cv. lC-503 (moderately resistant to Meloidogyne incognita). Cv. S-488 (resistant to Rotylenchulus reni/ormis) did not remain resistant in the presence of M. incognita though it did not lose its resistance in the presence of Rhizoctonia solani. Similarly, the resistance of cv. CO-4 to R. solani broke down in the presence of M. incognita but not in the presence of R. reni/ormis. Both R. reni/ormis and M. incognita, when present in association with R. solani, broke the resistance of cv. lC-244 against R. solani. The moderately resistant response of cvs. RC-8 and EC-4213A to R. reni/ormis and their complete resistance against R. solani broke down when simultaneously inoculated with both the nematode species or R. solani with either R. reni/ormis or M. incognita.

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