Analyses of genetic relationships in Nelumbo nucifera using nuclear ribosomal ITS sequence data, ISSR and RAPD markers

Despite the economic importance of Nelumbo nucifera, there have been no molecular studies on genetic relationships among cultivars in the species. In the present study 38 accessions were sampled including 37 accessions of N. nucifera or hybrids between N. nucifera and Nelumbo lutea and a single accession of N. lutea. In the ITS analyses, Chinese and Japanese lotus comprise a single cluster with a moderate bootstrap support 68% indicating there is very high similarity between them. Moreover, these ISSR and RAPD results also indicate that there is very close genetic relationship between Chinese and Japanese lotus. In the ISSR and RAPD analyses, although 38 accessions all are distinctly separately into two groups, viz. N. nucifera and N. lutea, there is a high Jaccard similarity coefficient (0.785 and 0.656) between the two species. In N. nucifera the two different groups of the species, viz. flower lotus and rhizome lotus accessions show clear genetic variations. Seed lotus accessions do not form a distinct cluster but are interspersed among the flower accessions indicating that seed lotus is phylogenetically close to flower lotus and they might originate from close wild lotus in genetic relationship. In flower lotus, big-flower type accessions and medium-small type accessions have obvious genetic variation, indicating height is an important criterion in the classification system of flower lotus.