Genetic Diversity Analysis And Salt Tolerance Study Of The Germplasm Resources Of Elytrigia Intermedia

Elytrigia intermedia?Host?Nevski is a common forage plant used for ecological environmental construction and for livestock production in China.It is also a wild parent material widely used in genetic improvement of wheat at home and abroad.It has the characteristics of cold resistance,salt and alkali resistance,barren and grazing tolerance,and has important economic and ecological value.Some reports have been done on the identification and evaluation of the salt tolerance of Elytrigia intermedia?Host?Nevski at home and abroad,with a genetic diversity analysis and salt tolerance study of Elytrigia intermedia?Host?Nevski germplasm materials,thus providing an important basis for the selection and identification of salt resistant materials of Elytrigia intermedia?Host?Nevski.In this experiment,the genetic diversity of 41 germplasm materials of Elytrigia intermedia?Host?Nevski were studied under different concentrations of NaCl,Na₂CO₃ and NaCl+Na₂CO₃.Under different salt gradient stresses,the seed germination and seedling growth of 5 parts of Elytrigia intermedia?Host?Nevski were studied.Under different salt gradient stresses,the salt tolerance of 2types of Elytrigia intermedia?Host?Nevski seedlings were analyzed by comparing the changes of physiological indexes and photosynthetic physiological characteristics.The main results are as follows:1.Genetic diversity of Elytrigia intermedia?Host?Nevski germplasm resources.Using 41 germplasm materials of Elytrigia intermedia?Host?Nevski to screen through 28 pairs of SSR primers,and eventually 18 SSR primers with clear bands,good amplification and stable polymorphism,64 alleles were amplified,57 of which were polymorphic;the percentage of polymorphic loci was 89.06%;the Shannon information index change range was 0.3600 to 0.6931;the PIC value ranged between 0.1845 and0.3749,and the selected SSR marker has a moderate polymorphism level.It showed that the selected primers could well reflect the genetic diversity of 41 Elytrigia intermedia?Host?Nevski.2.Study on the response of Elytrigia intermedia?Host?Nevski seeds to salt stress.Under the stress of different concentrations of NaCl,Na₂CO₃ and mixed salt elements?NaCl+Na₂CO₃?,the germination rate,germination potential,germination index,activity index,root length and bud length of 5 parts of Elytrigia intermedia?Host?Nevski decreased with the increase of concentration,while the relative salt damage rate increased with the increase of concentration.The effect of a low concentration of salt on seed germination was not significant.The inhibition degree of different kinds of salt on seed germination of Elytrigia intermedia?Host?Nevski was Na₂CO₃>mixed salt?NaCl+Na₂CO₃?>NaCl.When the concentration of NaCl was 200 mmol/L,Na₂CO₃was 50 mmol/L and mixed salt?NaCl+Na₂CO₃?was 100 mmol/L,all the Elytrigia intermedia?Host?Nevski seed germinated.The"Elytrigia intermedia 13"and"Elytrigia intermedia 24"had better salt tolerance.3.Study on the response of Elytrigia intermedia?Host?Nevski seedlings to salt stress.Through the analysis of physiological and photosynthetic indexes of"Elytrigia intermedia 13"and"Elytrigia intermedia 24"under different concentrations of salt stress,it was concluded that the content of malondialdehyde and free proline in the leaves of"Elytrigia intermedia 13"and"Elytrigia intermedia 24"were gradually accumulated,which enhanced their osmotic regulation ability.In the early stages of low concentration salt stress,the content of superoxide active enzyme,peroxidase,catalase and soluble enzyme were all increased.With the increment of stress time and salt concentration,the net photosynthetic rate?Pn?,stomatal conductance?Gs?,intercellular CO₂ concentration and transpiration rate?Tr?of"Elytrigia intermedia 13"and"Elytrigia intermedia 24"were both decreased,and were significantly lower than that of the control in the same period.Comparatively,the photosynthetic physiological parameters of Elytrigia intermedia 13 were lower than that of Elytrigia intermedia 24,which indicated that Elytrigia intermedia 13 had better salt tolerance than Elytrigia intermedia 24.