Development of Robust SCAR Markers that Distinguish the Six Cultivated Brassica Species and Subspecies of the U-triangle

Abstract

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.