AFLP fingerprinting in Capparis subgenus Capparis related to the commercial sources of capers 1, 2 1 and Mike F. Fay 2 1 Department of Plant Biology, University of Murcia, Murcia E-30100, Spain; 2 Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW9 3DS, UK; *Author for correspondence (e-mail: cpretel@um.es) Received 23 October 2002; accepted in revised form 28 June 2003 Key words: AFLP, Capparis, Capers, Cluster analysis, Genetic resources, Molecular techniques Abstract A genetic fingerprinting technique (AFLP) was used to determine the relationships among Capparis spp. Genetic distances, based on AFLP data were estimated for 45 accessions of Capparis species, from Spain, Morocco and Syria. The results of this analysis support the differentiation of four of the five taxa involved. The group of plants recognised as C. spinosa on the basis of morphological characters, includes several cultivars and appears in an intermediate position between C. orientalis and C. sicula and overlaps with C. orientalis. The other two species C. aegyptia and C. ovata are separate from the rest. Capparis spinosa had a low number of unique bands in comparison with the other species. Although these results cannot confirm the hybrid origin of C. spinosa, the distribution of the bands supports this hypothesis, the most likely parental species being C. orientalis and C. sicula. Introduction The subtropical genus Capparis L. is represented in the Mediterranean and Western Asia by several species included in subgenus Capparis Commer- cially speaking, capers are immature flower buds which have been pickled in vinegar or preserved in granular salt. Semi-mature fruits and young shoots with small leaves may also be pickled for use as a condiment. All commercial products are thought to come from the same species, C. spinosa L., which is also the type species of the section. The use of capers can be traced to ancient times. Capers have long been used as a condiment in Greece, being highly appreciated for their pungent and bitter fla- vour (Alvarruiz et al. 1990; Inocencio et al. 2000). Most of the material used for commercial purposes is gathered from the wild, but there are also several areas where caper plants are cultivated. The systematics of the genus Capparis are based on morphological characters such as leaf shape, flowers, spines, etc. (Zohary 1960; Greuter and Burdet 1984; Higton and Akeroyd 1991). The type of the section, C. spinosa, is morphologically clo- sely related to C. orientalis Duhamel and C. sicula Duhamel, and these two taxa have been included in C. spinosa by some authors (Table 1). Moreover, there is no clear idea about how many or which species are commercialised. (See Hammer 2001). Caper cultivars are commonly referred to as C. spinosa, although several belong to other taxa (Tables 2 and 3) and have also been investigated in this study. Traditional classification based on the obser- vation of both quantitative and qualitative macro-morphological characters could have a wide margin of error due to a lack of objectivity by the researcher and the effect of environmental Cristina Inocencio *, Robyn S. Cowan , Francisco Alcaraz , Diego Rivera 1 Genetic Resources and Crop Evolution # Springer 2005 52: 137–144, 2005.