Species delimitation and relationship in Crocus L. (Iridaceae)

Abstract

The genus Crocus L. (Iridaceae) is monophyletic and contains about 100 species throughout the world. Crocus species have horticultural, medicinal and pharmacological importance. Saffron is the dried styles of C. sativus and is one of the world’s most expensive spices by weight. Controversy exits about the taxonomy of the genus and the species relationship. Exploring genetic diversity and inter-specific cross-ability are important tasks for conservation of wild taxa and for breeding of cultivated C. sativus. The present study was performed to study genetic variability and population structure in five Crocus L. species including Crocus almehensis Brickell & Mathew, C. caspius Fischer & Meyer, C. speciosus Marschall von Biberstein, C. haussknechtii Boissier, and C. sativus L. by inter simple sequence repeat (ISSR) molecular markers. We also used published internal transcribed spacer (ITS) sequences to study species relationship and compare the results with ISSR data. The results revealed a high degree of genetic variability both within and among the studied species. Neighbor joining (NJ) tree and network analysis revealed that ISSR markers are useful in Crocus species delimitation. Population fragmentation occurred in C. caspius and C. sativus. Both ISSR and sequenced based analyses separated C. sativus from the other studied species. Close genetic affinity of C. sativus and C. pallisii and inter-specific gene flow was supported by both data sets.