Characterization of Kenyan Isolates of Fusarium udum from Pigeonpea [CaJanus cajan (L.) Millsp. ] by Cultural Characteristics, Aggressiveness and AFLP Analysis

Abstract

Isolates of Fusarium UdWI1 from plgeonpea (Cajanus cajan) plants with wilt symptoms were collected from various districts in Kenya and were characterized using cultural characteristics, aggressiveness and amplified fragment length polymorphism (AFLP). The 56 isolates of F. udum showed a high level of variability in aerial mycelia growth, pigmentation and radial mycelia growth (colony diameter) on potato dextrose agar. The aggressiveness of 17 isolates of F. udum on seven pigeonpea varieties varied and five aggressive groups were observed in the present study. There were no rela¬tionships among cultural characteristics and aggressive¬ness. AFLP analysis of the S6 isolates was tested for genetic variability using seven primer combinations. A total of 326 fragments was generated of which 121 were .~ ." -Iymorphic. Ten AFLP groups were identified among >Lne Kenyan isolates and, although they were not gen¬etically distinct, six AFLP subgroups were genetically distinct. AFLP had no relationship with cultural char¬acteristics, aggressiveness and geographical origin of the isolates. This is the first report on the study of gen¬etic variability of F. udum using DNA analysis