Genetic variation among Fusarium verticillioides isolates associated with Ethiopian maize kernels as revealed by AFLP analysis

Abstract

Amplified fragment length polymorphism (AFLP) was used to study the genetic variation among 80 F. verticillioides isolates from kernels of Ethiopian maize, collected from 20 different maize growing areas in four geographic regions. A total of 213 polymorphic fragments were obtained using six EcoRI/MseI primer combinations. Analysis of the data based on all 213 polymorphic AFLP fragments revealed high level of genetic variation in the F. verticillioides entities in Ethiopia. About 58% of the fragments generated were polymorphic. The genetic similarity among F. verticillioides isolates varied from 46% to 94% with a mean Dice similarity of 73%. Unweighted Pair Group Method with Arithmetic Average (UPGMA) analysis revealed two main groups and four subgroups. The principal coordinate analysis (PCO) also displayed two main groups that agreed with the results of UPGMA analysis, and there was no clear pattern of clustering of isolates according to geographic origin. Analysis of molecular variance: (AMOVA) showed that only 1.5% of the total genetic variation was between geographic regions, while 98.5% was among isolates from the same geographic regions of Ethiopia. Eighty distinct haplotypes were recognized among the 80 isolates analyzed. Hence, breeding efforts should concentrate on quantitative resistance that is effective against all genotypes of the pathogen.