Molecular characterization and identification of markers associated with partial resistance to phoma black stem in sunflower mutant lines using AFLP fingerprinting

The present study was undertaken to evaluate the genetic variability among gammairradiation induced sunflower mutant lines for partial resistance to Phoma black stem and also to identify putative molecular markers associated with partial resistance to Phoma black stem. A population of 60 mutants and their original line AS-613 were evaluated with an aggressive French isolate of Phoma macdonaldii (MP6) in controlled conditions. The experimental design was a completely randomized blocks with three replications. Variability on partial resistance and molecular markers, generated with 17 AFLP primer combinations was estimated. Some mutant lines were identified that consistently showed an altered Phoma black stem resistance. The dendrogram realized with the AFLP markers grouped the 61 genotypes into 8 major classes. Using multiple regression analysis, eight AFLP markers associated with partial resistance to Phoma black stem were identified. Prediction of the performance of all mutants for susceptibility to the disease based upon their marker profiles showed that none of them differed significantly from the observed values. These results provide interesting information for marker-assisted selection.