Forty olive (Olea europaea L.) cultivars from Valencia, Spain, were screened using random amplified-polymorphic DNA (RAPD) markers. Eighteen selected decamer primers produced 34 reproducible amplification fragments that were then used as polymorphic markers. The resulting combinations of these RAPD markers were used to discriminate 40 cultivars. Results were analyzed for similarity among cultivars and the relatedness of polymorphisms obtained between cultivars agreed with previous results using isozymes. Unweighted pair group method cluster analysis of their similarity values revealed two main groups divided according to geographic origin within Valencia. A third group, which included two Spanish cultivars from regions outside of Valencia, was clustered separately from the Valencian cultivars. RAPD technology proved useful in discriminating closely related cultivars. There was no apparent clustering of cultivars by fruit size or other morphological traits.
F. Sanz-Cortés, M.L. Badenes, S. Paz, A. Íñiguez and G. Llácer
Federico L. Iñiguez-Luy, Michell E. Sass, Geunhwa Jung, Mitrick A. Johns and James Nienhuis
This research describes the development of robust molecular descriptors that are reliable and easy to use (PCR-based) for the proper classification of the six cultivated Brassica L. species and subspecies that make up the U triangle. Sequence characterized amplified regions (SCAR) were derived from DNA fragments generated by randomly amplified polymorphic DNA (RAPD) primers that distinguished the U-triangle Brassica species: B. rapa L. (A, n = 10), B. nigra (L.) Koch (B, n = 8), B. oleracea L. (C, n = 9), B. juncea (L.) Czern (AB, n = 18), B. napus L. (AC, n = 19), and B. carinata Braun (BC, n = 17). The SCAR descriptors developed in this study reveal the presence-absence of a DNA fragment and sequence length polymorphisms to distinguish the three genomes (A, B, and C) of the six cultivated Brassica species. These markers should prove to be useful in revealing misclassifications at the subspecies level. The amplification of a single DNA fragment and reduced sensitivity to reaction conditions make these SCAR descriptors ideal to accurately classify and organize large numbers of cultivated Brassica accessions typically present in large germplasm collections.