Development Of SSR Markers In Coconut (Cocos Nucifera L.)

Coconut has been cultivated for thousands of years in the world,it was formed many cultivars,varieties and types by the long-term natural evaluation and artificial cultivation and demonstration.For a long time,there have no through study about the historical evolution and genetic relationships among coconut cultivars,which had greatly affected the extension of its superior varieties and the development of coconut industry.Therefore,it is necessary to find a powerful coconut genetic analysis instrument in order to study the genetic relationships among coconut cultivars thoroughly,to construct coconut genetic linkage map and to culture new superior coconut varieties.Base on these information,this research analyzed coconut by SSR that was based the technology of molecular marker which has been developed in recent years.The development and application of coconut SSR molecular maker is less,and the number of this molecular maker type is relatively low,which cannot meet the acquirement of quick identification of coconut cultivars,the analysis of coconut genetic relationships,the construction of coconut molecular genetic map,the location of some important coconut characteristics by QTL analysis,molecular maker assisted breeding and so on.Thus,We developed coconut SSR markers by Selectively Amplified Microsatellite and Transferability of Amplified Microsatellite.Meanwhile,those SSR markers identified and characterized by ourselves were used to analyze the genetic diversity and to construct fingerprints of 42 coconut cultivars that were collected from home and abroad.The major results are as follows:(1) This research successfully developed 84 SSR markers from coconut.The efficiency of SSR markers development was 22.1%from sequencing data to operationally useful loci.(2) The 5'anchored primers were substituted with designed special primers which enhanced the special and stable amplification of primer pairs,and improved the methods that were used before.(3) This is the first report about the use of SSR molecular markers developed from different genera of palm family was performed.10 coconut SSR primer pairs were used to amplify 39 different genera of palm family,the effective amplification is 90.5%,and the polymorphism level among the speciese of these genera was relatively high..(4) The arithmetical averages(UPGMA)cluster analysis was used to construct the dendrogram of 42 coconut cultivars from home and abroad by these primer pairs,and with the similarity coefficient criteria of 0.73,these accessions were clustered into 7 groups.(5) The genetic similarity coefficient of these 42 coconut cultivars ranged from 0.6 to 0.8.The highest was reached 0.961,and the lowest is 0.503.(6) Among these 5 Tall ecotypes and 8 Dwarf ecotypes,the genetic diversity of the former was higher than the latter.This result was coincided with the classification based on characteristics of coconut.(7) The genetic varision of the Tall ecotypes from Hainan Province China was less lower.(8) we can exactly distinguish the yellow and green Dwarf ecotypes at the DNA level.(9) In this study,we developed and characterized 84 coconut special SSR markers by SAM technique,which are useful for further research in coconut germplasm resources and breeding. What's more,the number of these primers was more than that was reported by other countries.