Construction Of Fingerprints And Analysis Of Genetic Diversity Using SSR Markers For Jujube Germplasms

Chinese jujube (Ziziphus jujuba Mill.) is an antive plant and the leading dry fruit. Chinese jujube is originated in China, has long history of cultivation, gremplasm resource of Chinese jujube are very abundant. SSRs (Simple Sequence Repeat), also called microsatellite DNA, are repeating sequences of 1-6 base pairs (bp), which becomes one of the most wide used fingerprint technologies. At present, the reports about construction of fingerprints using SSR markers for Jujube have a few, and the number of cultivars is less than 36.The research utilized the stable SSR system, which established by our research team.Then 263 Chinese jujube cultivars,5 sour jujube (Z. acidojujuba Cheng et Liu) cultivars and 2 Ber jujube (Z. mauritiana Lam.) cultivars were analyzed.The aim is to construct SSR fingerprint for large-scale jujube plant, which provide basis for cultivar identification, evoluation of genetic diversity and molecular assisted breeding. The main results are as follows:1.30 cultivars were firstly choosed to screen SSR primers.23 SSR primers with high polymorphism (JSSR88、JSSR93、JSSR97、JSSR102、JSSR128、JSSR129、JSSR131、 JSSR183、JSSR186、JSSR188、JSSR191、JSSR194、JSSR198、JSSR211、JSSR217、 JSSR222、JSSR239、JSSR244、JSSR262、JSSR284、JSSR314、JSSR417、JSSR438) were screened out.2.270 germplasms were analysed by 23 polymorphic SSR primers, and 122 allelic loci were detected, and the ratio of polymorphism was as high as 100%. Alleles amplified by each pair of primer ranged from 2 to 10, with a mean of 5.3. The polymorphic information content values (PIC) ranged from 0.36 to 0.72, with a mean of 0.55.3. By UPGMA cluster analysis, the results showed that the 23 pairs of primers could distinct the 270 materials. The genetic similarity ranged from 0.49 to 1.00, Ber Jujube was separated from Sour iujube and Chinese iujube at the clustering threshold of 0.520. At the clustering threshold of 0.754, and the remaining 268 species are divided into 13 classes, including two major classes and 11 small classes.4. Clustering results showed that Chinese jujube and sour jujube had closer genetic relationship compared with Ber jujube; generally the same cultivars from same origin showed closer genetic relationship, but not necessarily linked with the geographic distribution. The cultivars of A class were mostly from Shanxi, Shaanxi and Hebei which came from northern areas; the cultivars of Bland B3 subclass, came from B class, completely were from the northern areas; and the cultivars of I and III groups, came from B2 subclass, mostly were from the South area, the cultivars of II group from Hebei areas; the Chinese Jujube cultivars of 10 small classes mostly from southern areas.5. The research successfully constructed the SSR fingerprinting of 263 cultivars of Chinese jujube,5 types of sour jujube and 2 cultivars of ber jujube.