Molecular characterization of three Tunisian collections of cactus

Cactus (Opuntia spp.) is a popular and a welcomed plant in Tunisia. It is a multipurpose plant species that can withstand drought conditions and grow on marginal soils. Spiny and spineless cacti, mainly their cladodes, are used as forage for ruminants raised in arid and semi-arid zones. One of the major problems in Opuntia germplasm evaluation is genotypes identification. In this present study, Amplified Fragment Length Polymorphism (AFLP) markers were used to characterize the cactus germplasm present in three collections in Tunisia. The objectives of this study are: (i) to assess the usefulness of AFLP for distinguishing Opuntia accessions and (ii) to investigate genetic relationships among different species. Fifty seven cactus accessions were analysed with 10 primer combinations. Seven out of ten generated stable and interpretable profiles with a total of 519 bands. Genetic diversity was detected and we noticed a high genetic similarity within Opuntia ficus-indica varieties and their difference from the other Opuntia species was clearly revealed. Our results showed that AFLP markers provide a quantitative assessment of genetic similarity and diversity among several Opuntia species.