Studies On The Interspecific Relationships And Hybrid Origin Of The Genus Lycoris (Amaryllidaceae)

The genus Lycoris (amaryllidaceae) consist of about 20 species, distributed in warm temperate and subtropical zones of East Asia from southwestern China to Japan and southern Korea, with a few extending to northern Indochina and Nepal, 15 species of which are native to China. Lycoris species easily hybridize with each other; hybrids of morphological features vary frequently in nature and among cultivated genotypes. The chromosome numbers and karyotypes at species and genus level vary with wide range, including diploids triploids tetraploids and aneuploids, the traditional identification and classification of the genus Lycoris are largely based on morphology and color of flowers; leaf morphology is not of much value in identifications. Due to easy hybridization with each other and wide morphological features variation, it is difficult to identify and classify unknown or newly acquired accessions of Lycoris species by morphological features in nature and cultivation.Therefore, it is helpful to have information on genetic variation and relationships among these and some of the more recent collections of Lycoris from the wild and arboretum's nature hybrids. Any more, research on genetic variation and interspecific relationships among cultivated and wild species is needed for a well understanding of speciation in Lycoris.In present study, we collected 28 individuals presenting 16 doubtless species and several varieties. The joint use of RAPD and ISSR markers and ITS, trnL-F, atpB-rbcL sequences analysis seeks to find the phylogenetic relationships among Lycoris, the molecular documentation for possible interspecific hybridization in the genus Lycoris, and speciation by hybridization. The main results were as follows:1 interspecific relationship in Lycoris(1) The Lycoris species were divided into three main clusters, the first cluster included L. longituba, L. longituba var. flava, L. anhuiensis, L. chinensis and L. aurea, the molecular marker show genetic similarity coefficient value of 0.78 and 0.56, respectively. The same results are from ITS, trnL-F and atpB-rbcL sequences analysis.the bootsrap values are 74%, 95% and 97%, respectively.(2) The second cluster was comprised of species with a haploid genome of 11 subtelocentric chromosomes (A): L. sprengeri, L. radiata var. pumila, L. radiata var. radiata (diploids and triploids), L. haywardii and L. rosea. The analysis of RAPD and chloroplast DNA sequences suggests which cluster species are the primogenitors of the putative hybrids; the analysis of ISSR and ITS sequences are consistent with one another.(3) The third cluster was comprised of species with mixtures of subtelocentric, telocentric and metacentric chromosomes (M+T+A): L. houdyshelii, L. caldwellii, L. straminea, L. albiflora, L. incarnata and L. squamigera and two hybrids. Molecular data sets confirm all species of this cluster are hybrid origin.2 Hybrid origins in LycorisIn Lycoris frequent hybridization and wide morphological variation are prevalent; F1 plant rise upseed througth sexual and asexual propagate to rapid formation of new bulds. The molecular tools confirm natural hybrids distributed widely, hybridization play an important role in speciation in Lycoris.L. caldwellii and L. albiflora derived from hybridization between L. chinensis and L. sprengeri, the former inherited the 6M+10T unreduced gamete of L. chinensis, while 3M+5T of L. albiflora were from a reduced gamete of L. chinensis.s\m\\ai\ty, L. straminea origin from hybridization between L. chinensis and L. radiata var. pumila; L. incarnata and L. squamigera derived from hybridization between L.longituba and L. sprengeri; L. houdyshelii derived from hybridization between L.longituba and L. radiata var. pumila.; L.flavescens are from hybridization between L. sanguinea and L. chinensis; L. haywardii and L. rosea were from hybridization between L. sprengeri and L. radiata var. pumila. The fertile species have few additivity sites in ITS sequences, this could be explained by the sexsual propagation arosed the coevultion in fertile species which decreased the additivity sites of ITS. 3 the taxon's position of LycorisThe L. anhuiensis should not be recognized as distinct species status and be recognized as a variety of L. longituba.Molecular data support the status of diploid species L. radiata var. pumila, L radiata var. radiata and triploid species L. radiata var. radiata.Based on different outgroups species selected from amaryllidaceae, Liliaceae and orchidaceae, the combined molecular data sets; support the viewpoint that the genus Lycoris should put in amaryllidaceae.