Valuation And Selection Of Xanthoceras Sorbifolium Bunge Germplasm By Morphology Characteristics And SSR Markers

Xanthoceras sorbifolium Bunge is an important woody energy plant in the north of China with very rich germplasm resources.In order to valuate and select the genetic diversity of Xanthoceras sorbifolium Bunge,the germplasm resources of Xanthoceras sorbifolium in various regions of China were collected.Based on 32 phenotypic characteristics and 23 SSR molecular markers,the differences among populations and germplasm of Xanthoceras sorbifolium were systematically studied.The main findings were as follows:(1)The seed phenotype,oil composition and biodiesel traits of 14 populations of Xanthoceras sorbifolium were analyzed.The results showed that there were significant differences among the 14 populations based on these traits.According to these traits,14 populations were divided into 4 groups.The seeds of Yonghe and Qingyang had more advantage for biodiesel production,while the seeds of Ningan and Fangshan were relatively not suitable for biodiesel production in 14 populations.(2)The correlation analysis showed that the seed yield and the biodiesel traits were greatly affected by the environment,and the highest content of fatty acids in the seeds had no obvious relationship with the environmental factors.The lower fatty acids were more hereditary,while the higher fatty acids had a strong relationship with the phenotype of the seed.The biodiesel traits were affected by both the genetic and environmental factors.The selection of fatty acids based on phenotype can not only improve the information of genetic diversity of Xanthoceras sorbifolium germplasm resources,but also promote the selection of fatty acids and biodiesel traits through the phenotypic.This conclusion laid the foundation for choosing the sampling site according with the requirement of fatty acids.(3)The results showed that there were significant differences of seed phenotype,oil composition and biodiesel traits among 143 Xanthoceras sorbifolium germplasm.The principal component analysis(PCA)was used to select the four main characters of the key traits.For the proportion of 10%,14 good quality germplasm of Xanthoceras sorbifolium were selected,which number and origin were 14(Inner Mongolia Ongniud Banner),204(Inner Mongolia Ongniud Banner),158(Henan Shanxian),197(Inner Mongolia Ongniud Banner),187(Inner Mongolia Ongniud Banner),64(Inner Mongolia Ongniud Banner)162(Henan Shanxian),221(Henan Shanxian),75(Inner Mongolia Ongniud Banner),163(Shaanxi Zhidan),207(Hebei Chengde),59(Inner Mongolia Ongniud Banner)and 196(Inner Mongolia Ongniud Banner).These germplasm provided an important reference for cultivation of good quality germplasm.(4)Molecular markers showed that there were 80 allelic variations in 23 SSR loci,the Mean number of alleles per locus,effective alleles,Shannon’s information index,observed heterozygosity and expected heterozygosity were 3.48,2.46,0.99,0.73 and 0.58,respectively.The polymorphism ratio was 100%and the Mean polymorphism information content was 0.51.It can be seen that the highest polymorphic loci are QXH274,with high levels of genetic variation.(5)There were high genetic diversity among 11 populations of Xanthoceras sorbifolium.Genetic diversity from high to low in order were:Inner Mongolia Ar Horqin Banner,Liaoning Fuxin,Inner Mongolia Ongniud Banner,Shanxi Fangshan,Xinjiang Urumqi,Hebei Chengde,Shanxi Linfen,Henan Shanxian,Inner Mongolia Alxa Left Banner,and Shaanxi Zhidan.According to the consistency among populations,11 populations were divided into three groups.There was a significant positive correlation between the genetic distance and geographic distance of 11 populations.(6)The 138 Germplasm were classified into four groups,and their DNA fingerprints were drawn according to their amplified bands on different primers.These unique molecular identity cards were effective basis for distinguishing and identifying germplasm.(7)Core collections of Xanthoceras sorbifolium were constructed by stepwise clustering,which was 20%of total germplasm,with 25 Germplasm.Their germplasm numbers were:5,10,12,14,47,50,52,53,56,58,67,68,70,72,87,90,96,113,114,115,135,142,152,169,and 171.There was no significant difference between core collections and the original germplasm,so the core collections can fully represent the genetic diversity of original germplasm resources.(8)Eight core primers were obtained according to the number of alleles per locus,Shannon’s information index,and polymorphism information content.They were QBLB51,QXH643,QXHS371,QXH262,QXRB116,QXH365,QXH323 and QXH274.A total number of 104 germplasm can be distinguished with a Mean of 13 germplasm for per primer.This result can be ensured both the distinguished number of total germplasm and the number of germplasm by per primers.