Jujube variety identification based on SSR molecular markers and construction of DNA molecular identity card

The genetic relationship and genetic diversity of the main cultivars of Beijing jujube were analyzed by fluorescent SSR molecular markers, and the DNA molecular identity card of jujube varieties was constructed, which laid a foundation for the breeding, production and utilization of new jujube varieties.

A total of 103 jujube germplasm materials were collected, and the SSR fluorescent marker primers were screened. The molecular weight and alleles of the amplified bands were analyzed by multiple fluorescence capillary electrophoresis, and the corresponding amplified bands were obtained. Each jujube germplasm material was marked and the DNA molecular identity of the test samples was constructed.

Based on SSR molecular marker technology,19 pairs of SSR primers were screened for genetic diversity analysis of 103 jujube varieties, and 7 pairs of core gene combinations were screened to construct DNA molecular identity cards. The results showed that a total of 156 alleles were detected in 103 jujube cultivars by 19 pairs of primers after SSR-PCR amplification, with an average of 8.211 alleles per pair of primers. The effective alleles(Ne) ranged from 1.263 to 12.568, with an average of 3.467. Shannon's information index (I) ranged from 0.547 to 2.664, with an average of 1.351. The polymorphism information content (PIC) ranged from 0.32 to 0.917, with an average value of 0.603. The observed heterozygosity (Ho) and expected heterozygosity (He) ranged from 0.208 to 0.920 and 0.133 to 0.990, respectively. The average values of Ho and He were 0.639 and 0.637, showing a high heterozygosity. The genetic similarity coefficient was 0.85-0.98, and it was divided into two categories when the similarity coefficient was 0.85.

In summary, the genetic background of Jingzao 31, Jingzao 311, Mayazao and Yazao in Beijing is relatively narrow, the genetic similarity is high, and the gene exchange between different strains is less. The genetic relationship of Jingzao 60, Langjiayuanzao, Beijing Fengmiguan, Beijing paopaozao, Jingzao 28 and other jujubes is far away, and the genetic diversity is rich. The results provided an important basis for the identification of jujube varieties and the cultivation of new varieties.