Identification of wild and cultivated sunflower for breeding purposes by AFLP markers.

Amplified fragment length polymorphisms (AFLPs) represent one of the most powerful polymerase chain reaction (PCR)-based markers which enables one to discriminate single plants by DNA analysis. To date this technique has only been applied in cultivated sunflower to detect genetic diversity among oilseed inbred lines. In this article we report the use of AFLP markers to investigate the level of diversity within and between populations of Helianthus argophyllus collected in the Maputo area, Mozambique, both for taxonomic and breeding purposes. Three primer combinations gave the best results with 92 polymorphic fragments and were able to discriminate these wild endemic populations from H. annuus and from one of its interspecific hybrids. Most of the variation (71%) observed was within population, and the dendrogram based on shared fragments did not divide the H. argophyllus genotypes into distinct groups resembling different populations. Moreover the hybrid genotypes formed distinguishable subgroups with the cultivated sunflower genotype, confirming the suitability of this technique for taxonomic and phylogenetic studies. From a breeding point of view, although the 12 populations of H. argophyllus represent a new valuable genetic resource, only two of them possessed most of the variation observed, suggesting that they can be the most promising material for crossing with cultivated sunflower.