Study On Genetic Diversity By Morphological And ISSR Markers Of Pepper (Capsicum Annuum L) Germplasm Resources

. Pepper (Capsicum annuum L) is annual or perennial herbaceous plants belonging to the Solanaceae Capsicum, is one of the most important vegetable crops worldwide. Our country has abundant pepper germplasm resources., Strengthening research on pepper germplasm resources could improve the selection efficiency of parents and broaden the genetic base of breeding materials.Identifying the genetic diversity and genetic relationship of pepper germplasm resources have important theoretical and practical significance-for breeding new varieties. In this study, the phylogenetic analysis of81pepper germplasm materials from Hainan, Shanxi, Henan, Yunnan, Brazil, Thailand and the UK was conducted through morphological markers and ISSR molecular markers. The main conclusions are as follows:1、20morphological traits of81pepper materials were observed with reference to "pepper germplasm description specifications and data standards". The results showed that:the average variation coefficient of the20morphological traits was40.91%, the variation coefficient for each trait was greater than18%, and the average Shannon diversity information index was6.21, which proved that pepper germplasm materials had a wide variation.2、The cluster analysis of20morphological traits was performed with SPSS16.0statistical software, the81pepper germplasm materials were divided into two categories in the scale of24and can be divided into five categories in the scale of16.3、The genomic DNA of pepper materials was extracted by using improved CTAB method, the high purity and good quality of DNA can meet the need of genetic diversity analysis of ISSR marker.4、The pepper ISSR-PCR reaction system was optimized using orthogonal design. The total reaction volume was20μL including DNA template40ng,10umol/p.l primers1.0μl, and2×premix Taq(?)10μL. The amplification program was94℃predenaturation5min;94℃degeneration30S,48～57℃anneal50s (annealing temperature depend on the Tm of each primer),72℃extension2min,38cycles; f72℃final extension10min, then stored at4℃.5、17ISSR primers were screened out from100ISSR primers which produced196bands, of which193bands (98.5%) showed polymorphic; the genetic similarity coefficient of the81pepper germplasm materials were between0.449～0.908. The cluster analysis of ISSR amplification results was conducted Using UPGMA method of NTSYS-pc2.10statistical software, the result showed that81pepper germplasm materials can be divided into five categories at.the genetic similarity coefficient GS=0.74(L1).6、The cluster results of morphological markers and ISSR markers are Similar, which could distinguish the Capsicum chinense Jacquin、Capsicum annuum var.grossum sendt. and Capsicum annuum L.var.fasciculatum sturt. L262and L508were clustered into one group and L522was clustered into one group separately. But, there are some differences in the classification of Capsicum annuum L.var.longum sent.and specific pepper varieties between morphological markers and ISSR marker analysis. In short, combining morphological markers and molecular markers could fully explain the classification results and illuminate-the genetic relationship of the tested materials clearly.