Study On Genetic Diversity Of Germplasm Resources Of Narcissus Tazetta

Narcissus tazetta L.is a perennial root herb of the Narcissus genus of Amaryllidaceae.It is an important ornamental flower in winter because of its rich flower branches and fragrant flowers.The development of daffodils industry is seriously restricted because of the late start of the research on daffodils in our country,the few varieties,the single color and the long breeding cycle of new varieties.By collecting and sorting out the existing resources of narcissus in Fujian,the genetic diversity analysis was carried out from the botanical and biological characteristics,cytological and molecular biological levels of the resources of Narcissus tazetta.In order to provide theoretical basis and data support for the introduction,breeding and cultivation of Narcissus tazetta,the relationship among the resources of Narcissus tazettawas studied.The main results obtained are as follows:1.The botanical characters and biological characteristics of 15 materials of Narcissus tazetta outdoor-cropped in Zhangzhou.The ornamental characteristics of the plants were significant among the resources.The results showed that the plants started bud-bursting from late October to late December,began flower-spiking in late November and ended in late January,and bloomed from early December to late February in the following year.The flowering period lasts for 81 days.There were 4major flower colors that included bicolor flower type,white flower type,yellow flower type and other types.According to the flowering period,there are three type:early,middle and late.This study can provide reference for selection of new Narcissus varieties.2.The karyotype and chromosome number of 8 kinds of Narcissus tazetta root tip cells were analyzed by conventional compression technique.The result indicated that there were two diploidand six triploids in eight Narcissus.The detailed karyotypes of the five cultivars are as follows: ‘Erlicheer' was 2n=3x=30=2(9sm+1st)+(8sm+2st),‘Galilee' was 2n=3x=30=2(5sm+5st)+(5sm+5st),‘Golden rain' was2n=2x=20=10sm+10st(SAT),‘Winter Sun' was 2n=3x=30=2(3sm+7st)+(3m+6st+1t),‘Ziva' was 2n=2x=22=8sm+14st,‘Avalanche' was 2n=3x=30=2(3sm+7st)+(6sm+4st),‘Cai-wang' was 2n=3x=30=12m+6sm+12st,‘Swallow' was 2n=3x=30=2(3m+5sm+2st)+(1m+7sm+1st+1t).The results of chromosome number and karyotype analysis of eight Narcissus species not only provide cytological basis in classification,but alsoguidance for the selection of new varieties by using these resources.3.SSR marker is an important molecular marker for genetic diversity and germplasm identification of Narcissus.In order to develop new SSR markers,SSR loci of Narcissus tazetta 'Yunxiang' at different flowering stages transcriptome were searched by using bioinformatics software MISA,and were designed specific SSR primers.The results showed that 14581 SSR loci were found in the different flowering stages transcriptome of Narcissus tazetta 'Yunxiang',which were distributed in 12361 unigenes.The frequency of SSR was 19.95%,with an average of1 SSR locus per 3.87 kb.The length of SSR sequence was different from that of12-30 bp base pair,and the repeat times of SSR motif was between 4-24.Among them,the repeat-type of Mono-nucleotide acid was 52.82% of the total SSR,followed by Di-nucleotide and Tri-nucleotide,16.72% and 26.92%,respectively.In addition to Mono-nucleotide repeats,the frequency of repeat motif AG/CT was the highest,followed by AAG/CTT.The Primer 3.0 software was used to design and screen the primers to obtain 16355 pairs of ssr primers.Random selection of 30 pairs primers and RCP amplification,A clear and repeatable band was amplified by 18 pairs of primers,and the amplification rate was 80%.In conclusion,the unigenes information in the sequencing results of Narcissus tazetta 'Yunxiang' transcriptome at different flowering stages can be used as an effective source for the development of SSR markers.The ssr loci in this transcript group have higher frequency,more species and higher polymorphism potential.It is a promising method for germplasm identification,molecular breeding and genetic diversity of narcissus.