Genetic variation and population structure in a Eurasian collection of Isatis tinctoria L.

Isatis tinctoria L. is a biennial species which was cultivated in Europe until the 18th century to produce indigo, a pigment used for dyestuffs. Today there is renewed interest in this ancient crop because of a market demand for natural dyes. Cultivation of the species appears to be particularly suitable for marginal areas. Information about the evolutionary and genetic patterns of I. tinctoria is needed if varieties or to be developed in future breeding programs. The aim of this study was to assess the genetic variation and similarity levels among and within natural populations of I. tinctoria from Europe and central Asia. Fifteen populations were used to carry out the genetic analyses with AFLP and SAMPL molecular markers. Data collected were analysed by the UPGMA method and were used to perform AMOVA. The results are consistent with the hypothesis that the crop originated in an eastern centre of origin and moved westward giving rise to a gene pool that is quite different from the original. The wide within-population variation revealed by this study suggests that effective breeding work to develop varieties suitable for marginal environments can be carried out easily.