REACTION OF SOM E OIL PALM (ELAE1S GUINEENSIS JACQ) TENERA PROGENIES TO FUSARIUM OXYSPORUM f. sp, ELAEIDIS CAUSAL AGENT OF VASCULAR W ILT DISEASE OF OIL PALM

ABSTRACT

Studies were carried out on the reaction o f some oil palm tenera progenies to Fusarium oxysporum f sp elaeidis (FOFSE) isolates isolated from the Crops Research Institute and Oil Palm Research Institute plantations, in Akumadan and Kusi respectively. Four isolates, P. 38, P.50, P.459 and P.568 were obtained from Akumadan and the remaining one, P. 93 from Kusi. The growth and cultural characteristics of the isolates were studied on Dehydrated Potato Dextrose Agar (PDA), Fresh Potato Dextrose Agar and Potato Sucrose Agar (PSA). Fresh PDA and PSA were found to he the most suitable media for culturing FOFSE. Cultural characteristics o f the isolates on agar plates showed differences with respect to the pigments produced All the isolates also had different measurements with respect to length and width o f the macroconidia produced. Four isolates, namely P. 38, P.50, P. 93 and P. 459 were found to be variants o f FOFSE while Isolate P.568 was found to be either Fusarium solani or a mixture o f this and FOFSE. Six tenera progenies, G9, G25, G30, G44, G51 and G84 selected from Oil Palm Research Institute (OPRI) breeding stock at Kusi were tested against the Fusarium isolates using different inoculation methods. Results obtained from sensitivity tests using germinated nuts o f the progeneies in the laboratory were inconclusive. About 80% o f the germinated nuts reacted differently to the various isolates.

With regard to susceptibility and virulence tests carried out in the screen house using seedlings, progeny G30 was found to be the most resistant while progeny G44 was the most susceptible to the fungal isolates. O f the studied FOFSE isolates, isolate P. 38 and P459 were found to be highly virulent while P. 50 was the least virulent.