Salt-talerance Evaluation And Genetic Diversity Analysis On Soybean Germplasm Resources

Salinization of soil is one of the major abiotic-stress that influences agricultural production and environment. With the growing of world's population and the decreasing of field, how to develop and utilize salinized-soil becomes more and more important. To increase food production for the need of population growing and maintain sustainable development of agriculture, the most economic and efficiency strategy to improve and utilize salinized-soil is screening salt-tolerant germplasm resources, discovering and cloning the genes related to salt-tolerance, and breeding new varieties tolerant to salt-stress using biotechniques.Based on 941 accessions of soybean germplasm introduced from China&U.S.A, the aim of this study is to screen elite soybean germplasm of salt-tolerance by evaluation of salt-tolerant capacity at both stages of germination and seedling. This study also analysis genetic diversity of excellent salt-tolerant soybean by means of SSR molecular data and provide proof of salt-tolerant soybean germplasm. The study has gotten following results:1. By evaluation of salt tolerance at the stage of germination , 21 high tolerant (grade 1) soybean accessions and 58 tolerant (grade 2) soybean accessions had been screened. Besides, 256 medium tolerant (grade 3) soybean accessions, 418 senstive tolerant (grade 4) soybean accessions and high sensitive (grade five) soybean accessions had been evaluated. By evaluation of salt tolerance at the stage of seedling, 10 high tolerant (grade 1) soybean accessions and 39 tolerant (grade 2) soybean accessions had been screened. In addition, 143 medium tolerant (grade 3) soybean accessions, 277 sensitive (grade 4) soybean accessions and 260 high sensitive (grade 5) soybean accessions had been evaluated. The evaluation of salt tolerant at both stages of germination and seedling in soybean germplasm showed the majority of soybean accessions were in the grade 3 or 4.2. A total of 110 soybean accessions, in cluding 63 soybean accessions from China and 47 soybean accessions from USA, were analysed with 50 SSR marker. The result showed that there was an average of alleles per locus with a totol of 368 alleles at 50 SSR loci; the mean value of Simpson index and Shannon-weaver index were 0.7265 and 1.6090 respectively. Among 50 SSR primers, Satt281 and Satt157 had more alleles, 16, and higher Simpson index.3. Based on data of alleles, Simpson index and Shannon-weaver index, the result of comparing between domestic soybean germplasm and American soybean germplasm had showed that the former had higher genetic diversity.4. Based on data of SSR, 110 salt tolerant soybean accessions were clustered into 15 groups, SM index from 0.62 to 0.96. 80% American soybean accessions belonged to the 1st group with other domestic accessions. The nine one of eleven soybean accessions from Jiangxi Province were in the same group with other accessions. Four soybean accessions from Hunan Province were in the same group without other one. But in the whole 110 salt tolerant soybean accessions were clustered irregularly, which showed 110 accessions were differentiated in the molecular level. 5. Based on data of SSR, 63 domestic soybean accessions were clustered into 8 groups. In the whole 63 salt tolerant soybean accessions were clustered irregularly, which showed the 67 accessions were differentiated in the molecular level. But those accessions in the same group were from the same province or area.