Study On Genetic Relationship Of European Plum(prunus Domestica L.) Germplasm Resources In Xinjiang

In this resesrch, 30 individual plants that came from 5 types of Wild European Plum, Jiashi Smoked Plum, Tacheng Smoked Plum, Tacheng Binzi and Introduced European Plum varieties were the main study objects. In order to reveal the germplasm characteristics and the genetic relationships of P. domestica L. in Xinjiang and lay a theoretical foundation for protecting and developing of P. domestica L. germplasm resources in Xinjiang, the differences on botanical character, pollen micro morphological character, chromosomes karyotype character and ISSR molecular marker genetic character of them were compared and observed. The research findings showed:1.The 30 tested individuals all showed varying degrees of diversity on 58 indicators of floral stem length, corolla diameter and so on. Among them, the variable coefficient of single fruit weight was the hightest(69.8%), and the variable coefficient of petaline number was the minimum(5.4%). ‘Weight of fruit factor’, ‘pistil factor’, ‘size of leaves factor’, ‘internal quality factor’, ‘shape of leaves factor’ and so on 11 principal components on which cumulative contribution reached 90.632% were the main reason that caused botanical characteristics differences on germplasm resources of P. domestica L. in Xinjiang. In cluster analysis of botanical character, Wild European Plum was similar with local Smoked Plum varieties led by Jiashi Smoked Plum; Introduced European Plum varieties were similar with Tacheng European Plum resources led by Tacheng Binzi.2.The pollen grains of tested P. domestica L. in Xinjiang were all isopolar and actinomorphy single pollen. The shapes of pollen were always prolate. The germinated organ belonged to N3P4C3 type. The average polar axis length ranged from 27.70 μm to 41.47 μm, and the equatorial axis length ranged from 14.67 μm to 21.34 μm. The polar axis and equatorial axis variation coefficients were 8.88% and 7.51%, respectively. On exine ornamentation, both Tacheng Binzi and Tacheng Smoked Plum belonged to “fringe-perforate” type mostly. But Jiashi Smoked Plum, introduced European Plum varieties and Wild European Plum mainly belonged to “verrucous-perforate”, “fringe/cerebroid-perforate” and “wide fringe/verrucous-perforate”, respectively. According to exine ornamentation, the evolution degree of Xinjiang European plum types from low to high might be as follow: Jiashi Smoked Plum, Wild European Plum, introduced European Plum varieties, Tacheng Smoked Plum, Tacheng Binzi. Cluster analysis of the pollen morphology characteristics showed that Jiashi Smoked Plum and Wild European Plum had the nearly genetic relationship. However, the introduced European Plum varieties and the Tacheng European Plum resourses had the nearly genetic relationship.3.The ploidy levels of 5 types P. domestica L. in Xinjiang were all hexaploid(2n=6x=48). Most tested materials contained different numbers of ‘m’ and ‘sm’ chromosomes. All tested materials contained L, M2, M1 and s in total 4 types of relative length index. Arm ratio means of each types European Plum ranged from 1.46 to 1.69. Asymmetrical karyotype coefficient ranged from 59.13% to 62.34%. Karyotype types were all ‘2B’. The karyotype evolutionary trends of European Plum in Xinjiang were from symmetric to asymmetric in general. Cluster analysis of karyotype characteristic showed that introduced European Plum varieties and Tacheng Binzi had the nearly genetic relationship. However, Tacheng Smoked Plum and Wild European Plum had the nearly genetic relationship. Jiashi Smoked Plum had its particularity on karyotype characteristic.4.ISSR molecular markers results of 30 tested individuals showed that a total of 317 bands were amplified by 16 primers. And there were 77.60% polymorphic bands among the amplified bands. The average gene diversity within the 5 germplasm types of P. domestica(Hs) was 0.090 1; the Nei’s genetic differentiation coefficient(Gst) was 0.647 1; the gene flow among different germplasm types(Nm) was 0.272 7. And most of the genetic similarity coefficients ranged from 0.555 2 to 0.996 8. It indicated that the P. domestica germplasm resources in Xinjiang had a certain genetic diversity. And the genetic variation among different germplasm types of P. domestica in Xinjiang was much greater than that within germplasm types. The cluster analysis showed that the tested individuals were divided into 4 major groups in total at genetic similarity coefficient of 0.719 and 0.949. Among all the groups, the group of Wild European Plum had the lowest genetic diversity, while the group of Tacheng Smoked Plum and Tacheng Binzi had the most abundant genetic diversity. There were very close genetic relationships between Jiashi Smoked Plum and Wild European Plum, and among the introduced European Plum varieties, Tacheng Smoked Plum and Tacheng Binzi.