Leaf spot disease caused by Alternaria helianthi (Hansf.) is an important
fungal disease of sunflower in India and elsewhere. Non-availability of known
sources for resistance to Alternaria is a major constraint in sunflower breeding.
Hence, seeds of sunflower genotypes were subjected to gamma-irradiation
to develop mutant populations. Mutants were selected from the M2 generation
based on percent disease incidence and were passed on to the M3 generation.
Genomic DNA from leaf samples was evaluated by PCR amplification using
random decamer primers and the amplified DNA fragments from mutants
were compared with their respective controls. Single marker and stepwise
regression analysis carried out in relation to percent disease index indicate
that the alleles OPC5-B, K, J, OPA12-D and OPA15-A are strongly associated
with Alternaria helianthi resistance.