Determination Of Cold Resistance And Fingerprint Construction Of Poplar Clones

The efficient cultivation and utilization of poplar resources plays an important role in China's forestry industry development and ecological environmental protection as Poplar is an important industrial timber and economic tree species in our country.In this experiment,18 new poplar clones including three newly Populus alba clones,five Populus×euramericana clones from Italy and their close relatives in the northwest region in China were used as test materials.The cold resistance study was carried out using the clones of the Populus tomentosa clones and Populus deltoides clones group.The changes of the protective enzyme activities of SOD,POD,CAT,MDA content and soluble protein content of each poplar clone under a temperature gradient of-15 ?--35 ? were measured.Combining the comprehensive evaluation method of membership function and cluster analysis to compare and rank the cold resistance differences of clones,it provides a theoretical basis for the research of poplar tree cold resistance and the selection and promotion of new strains.The STR fluorescence detection technology was used to detect the amplification results of 12 pairs of SSR primers of poplar clones,and to construct fingerprints for each poplar clone,in order to lay the foundation for identification and selection of poplar genetic resources.The main conclusions of this test are as follows:1)With reference to the comprehensive evaluation results of membership functions of poplar clones,the order of resistance in Populus tomentosa clones to cold is: ‘A50'> ‘Qinbaiyang1hao'> ‘84K'> ‘Xinjiangyang'>‘A46'>‘I-101'> ‘Maobaiyang'> ‘A39';the order of resistance in Populus×euramericana clones to cold is: ‘Qg'> ‘Ta'> ‘Pa'> ‘Ti'> ‘La'> ‘Zhonglin46hao'> ‘I-107'.The results of cluster analysis show that,the poplar clone group with strong cold resistance includes Populus abla clones ‘A50',‘Qinbaiyang1hao',‘84K',Populus×euramericana clones ‘Qg',‘Ta'.2)The changes of physiological and biochemical indicators under low temperature stress showed a trend of increasing first and then decreasing,which was in line with the results of previous studies.There are different degrees of correlation among the 6 cold resistance indicators.According to the 6 indicators,the establishment of a poplar cold resistance evaluation system for testing has certain reliability.3)The average SSR primer polymorphism sites of 18 poplar clones are 7.6,the average effective allele number is 5.4,the average Shannon index(I)is 1.8015,and the average Nei's gene diversity index(H)is 0.7948,the variation range of genetic similarity coefficient is 0.549-0.978,indicating that the tested poplar clones have rich polymorphism in SSR sequence.4)Using 12 pairs of SSR polymorphic primers to construct fingerprints of 18 poplar clones and formulate unique identity information for them.SSR molecular marker technology is feasible in the analysis of poplar genetic differences,and can provide a certain theoretical basis for the selection of poplar clones.