Evaluating Genetic Diversity And Establishment Of A Core Collection Of Chinese Jujube

Chinese jujube (Ziziphus jujuba Mill), belonging to the Rhamnaceae, has important economic value because of its high nutritional value. Jujube has rich variety resources but the common existence of synonymy and homonymy caused inconvenient and disorder for preserving and research of jujube germplasm resources. In this research, genetic diversity and clustering of jujube germplasm resources were analyzed using 24 SSR markers aiming to reveal the genetic diversity level and to confirm the relationship and classification of jujube accessions. Meanwhile, the establishing of core collection of jujube can provide foundation for the scientific and systematic preserving, research and utilization of jujube germplasm resources and ultimately promote the development of genetic breeding of jujube. Main results for this study are as follows:1.963 germplasms from Chinese Jujube Experimental Station of Beijing Forestry University and the National depository of Chinese jujube germplasm were classified to four varieties:diploid jujube, wild jujube(Z. jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow), triploid jujube and Taiwan green jujube (Z. mauritiana Lam.). The level of genetic diversity decreased successively from diploid jujube to Taiwan green jujube. All these groups except Taiwan green jujube have high genetic diversity levels. 622 genotypes and 91 germplasms with the same name were found in 947 jujube germplasms(diploid jujube and wild jujube). But there exist Synonymy and homonymy. Both of Cangzhou and Taigu repositories have similar high level of genetic diversity, but the former has more rare alleles.2. Among 24 loci,215 alleles with 59.53% rare alleles were detected from 622 germplasms. The average alleles and average expected heterozygosity are 8.96 and 0.61 respectively. The Shannon information index is 1.23 and polymorphism information content is 0.56 which means jujube germplasm resources have high level of genetic diversity. Among 24 SSR primers, BFU0308 has the highest discrimination capability while BFU0521 has the lowest.3.622 germplasm were divided into 3 subgroups by "Structure" corresponding to the cluster result of "PowerMarker". This result is of great significant to the understanding of genetic relationship between jujube germplasms.4. Core collection consist of 150 germplasm were established by M sampling strategy with 622 germplasm as original group and with combination of 20 varieties selected by crack resistance, cold resistance and size of fruit. Allele attention is as high as 99.53% which means there is no significant difference between core collection and original germplasm. So this core collection can well represent the genetic diversity of Chinese jujube germplasm resources.