Salt Tolerance Screening And Genetic Diversity Analysis Of Helianthus Tuberosus L.

The saline soil which widely distributed over the world is an important reserve land resource.Therefore,it is of great significance to develop and utilize the salinized soil to ensure the security of human grain.The practice has proved that the bio-improvement method is currently recognized as the most economical,effective and long-lasting method for improving saline soil,and also is an important research direction for the development and utilization of salinized soil.Helianthus tuberosus L.is a kind of energy plant with important potential utilizing value due to its large biomass,strong stress resistance and poor demand for water and fertilizer.Therefore,cultivating high salt-tolerant Jerusalem artichoke varieties,screening and identifying the high salt tolerance of Jerusalem artichoke germplasm materials,for the effective exploitation and utilization of saline soil and improvement of human living habitat has important practical implications.In this study,36 excellent Jerusalem artichoke germplasm resources were selected as the research materials.By direct planting of Jerusalem artichoke on the coastal mud flat,the salt tolerance of different Jerusalem artichoke strains was evaluated by the classification evaluation method and fuzzy membership function method.Moreover,by means of AFLP(amplified fragment length polymorphism)molecular markers,the genetic structure and genetic relationship between germplasm resources were studied.This study laid solid theoretical basis for the selection of parents and the use of heterosis in the selection of new varieties.The main results are as follows:(1)The results of salt damage classification method and fuzzy membership function method are highly consistent.It proves that the two methods are reliable methods for identification of salt tolerance of Jerusalem artichoke.The survival rate can be used instead of salt damage index to identify salt tolerance in rough screening.Some indexes of tuber are very important for salt tolerance screening of Jerusalem artichoke strains.(2)36 Jerusalem artichoke germplasm resources can be divided into 4 types: highly salt tolerant strains,moderate salt tolerant strains,low salt tolerant strains and salt sensitive strains.Among them,2 strains of LZJ040 and LZJ119 are high salt tolerant strains,accounting for 5.56% of the tested materials,and 10 strains of LZJ006,LZJ023,LZJ035,LZJ038,LZJ039,LZJ042,LZJ043,LZJ050,LZJ055 and LZJ116 are medium salt resistant strains,accounting for 27.78% of the tested materials.A total of 9 strains of LZJ007,LZJ029,LZJ030,LZJ032,LZJ033,LZJ034,LZJ036,LZJ044 and LZJ111 are low salt tolerant strains,which accounted for 25% of the tested materials,and 15 products,including LZJ001,LZJ002,LZJ004,LZJ005,LZJ008,LZJ009,LZJ010,LZJ012 and LZJ013,are salt sensitive strains,accounting for 41.67% of the tested materials.(3)1390 loci are amplified by 10 pairs of primers,of which 1380 polymorphic loci are found.The percentage of polymorphic loci is 98.24%,the observed number of alleles is 1.999,the effective number of alleles is 1.351,the Shannon's information index is 0.373,and the expected heterozygosity is 0.229.The genetic distance between the Jerusalem artichoke material is 0.22-0.41,with an average of 0.32,and the similarity coefficient is 0.59-0.78,with a average of 0.68.It indicates that the genetic diversity between the Jerusalem artichoke materials is high.When the similarity coefficient is 0.666,the cluster analysis of unweighted pair-group method with arithmetic means shows that Jerusalem artichoke germplasm resources can be divided into 2 groups.The germplasm resources of Jerusalem artichoke originated from the same area are generally clustered together and thus showed high geographic correlation.(4)European strains and Asian strains have certain genetic differentiation and are far from each other in kin relationship,and European groups have higher genetic diversity.6.40% of the total genetic variation occur among groups,and 93.60% of the variation occur within groups.The genetic variation between the 2 resource groups identified by AFLP and the 4 resource groups obtained from the salt tolerance screening are roughly equal to the genetic variation among the different geographical distribution germplasm resources,indicating the variation within groups mainly comes from the genetic variation of the species.(5)The results of cluster analysis were in accordance with the results based on the classification of tuber color and of salt tolerance screening,which showed that the two had a certain correlation.However,the results of clustering in most strains do not coincide.It may be that the traditional morphological classification methods can not fully reflect the relationship between the resources of Jerusalem artichoke.On the other hand,salt tolerance of plants is a quantitative trait,which is controlled by multiple genes,and different salt tolerant genes are controlled and expressed differently.