Study On The Genetic Relationships Between Different Gender Types Of Pistacia Chinensis Bunge

Pistacia chinensis Bunge distributed widely in China and has a broad development prospect as an important biodiesel tree.The discovery of the monoecious P.chinensis,broke the bottleneck of dioecious plants and increased fruit yield.So far,some studies on monoecious P.chinensis have been reported.Nevertheless,no attention has been paid to genetic diversity and relationships studies in the monoecious P.chinensis.In the current study,the distribution of female and male flowers from four wild P.chinensis populations in Henan and Hebei regions were investigated,the genetic relationships and population structure of 140 samples of P.chinensis were analyzed using SSR markers,and the stability of gender variation of grafted trees was observed and analyzed year by year,which provides basic data for the study on the origin and evolution of monoecious P.chinensis,and provides theoretical basis for the application of monoecious trees in production.The results are as follows:1.Compared with mixed inflorescences,there were more bisexual inflorescences on the monoecious trees in Maanshan and Xiqi populations from Henan region,and the number of female inflorescences and male inflorescences is almost equal.Nevertheless,there were more mixed inflorescences than bisexual inflorescences on the monoecious trees in Laogu and Yangjiaan populations from Hebei region,and the number of female inflorescences is more than the number of male inflorescences.2.It was found that the gender expressions of grafted trees were not completely consistent with that of the scions,which indicated that monoecious trees probably did not originate from a stable bud mutation.In addition,the gender(flower type)phenotypes of P.chinensis were unstable,and gender types of the single branch could change within a year.3.Different monoecious trees have different SSR genotype,while there was no difference in the SSR genotype from gDNA samples collected at different locations on the same monoecious tree.4.A total of 52 alleles were amplified using the 14 SSR loci.The mean genetic differentiation coefficient(Fst)was 0.0316.Therefore,approximately 96.84%of the genetic variation occurred within populations,and 3.16%of the genetic variation occurred among populations.The average value of the gene flow parameter(Nm)being 7.6490(Nm>1),which indicated that gene exchange played an important role in genetic differentiation of P.chinensis than genetic drift.5.The clustering results showed that the number of clusters between monoecious samples and monoecious,female and male dioecious samples were three,two,and two respectively with the genetic correlation coefficient of 0.86 as the threshold in Maanshan and Xiqi populations from Henan region,three gender types of P.chinensis samples have close relationships.The number of clusters between monoecious samples and monoecious and female dioecious samples were three and eight respectively with the genetic correlation coefficient of 0.81 as the threshold in Laogu and Yangjiaan populations from Hebei region,monoecious trees showed close genetic relationships with other monoecious trees and with female dioecious trees.The monoecious samples clustered not only with local P.chinensis,but also with P.chinensis from other regions,which indicated that the genetic relationships of four wild populations of P.chinensis in Henan and Hebei regions without obvious regional characteristics.The genetic relationship of P.chinensis has nothing to do with the sex of the plant and population.