Physiology And Genetic Diversity Analysis Of Salt-tolerance In Soybean Cultivar "Zhongye No.1"

The aim of this study was to explain physiology of soybean salt tolerance, establish an appropriate salt-tolerance identification system and reveal the differences of genetic or physiological factors of salt-tolerance in same population analyzed by SSR markers.By measured amounts of glycinebetaine and proline in the shoots and the roots of soybean treated with difference NaCl concentration and time, it showed that glycinebetaine, one of major organic osmolytes, can be induced and accumulated in root cells under salt stress. Plant can maintain osmotic balance and normal metabolism function by regulated the amount of glycinebetaine based on salt concentration. Proline accumulation in the root cells was a major functional role in osmoregulation for plant tolerance to salt stress. But in shoots cells, it cannot find any relationship between amount of glycinebetaine and proline and plant salt tolerance, it suggested that the amount of glycinebetaine and proline in soybean shoots is not salt tolerance index. The character of injuring reaction was appeared with the increase of proline in shoots.The identification system based on salt tolerant efficiency was established with combination of quality and quantity to evaluate plant salt tolerance. This system makes the evaluation of salt tolerance become easy, convenient and standard. The identification method showed not only the salt tolerance of the material, but also the tolerant stability. Few literatures mentioned the tolerant stability of experiment materials. It is significant in salt tolerant genetic and breeding research that we proposed the tolerant stability of experiment materials as a part of salt tolerance evaluation.Total 232 pairs of SSR primers were used to amplify DNA from the tolerance and sensitive gene pools in "Zhongye No.l". The results showed that 5 SSR polymorphic loci lied on 3 linkage groups. According to the results of "Zhongye No.l" population screened with 5 SSR pair primers, "Zhongye No.l" could be grouped into A and B that have similar genetic background. Using simple matching coefficient to estimate gene frequency and reckon the genetic similarities, the GS of group A and B was 97.85%. It indicated group A and B came from the same hybridization combination and similar genetic background. It estimated that "Zhongye No.l" was selected from two sister strains mixed in high generation.Significance of differences between group A and B for salt tolerance was estimated using Mest, the difference of salt tolerance were remarkable significant. It suggested the difference in salt tolerance of two groups maybe relate with SSR polymorphic loci on linkage groups between group A and B. The genes associated with salt resistance maybe located on the polymorphic regions that sart318 and sct₀94 from satt601 to satt556 located on LG B2, satt!86 and satt310 from satt301 to satt031 located on LG D2 and satt257 from sat₀91 to satt022 located on LG N.Compared the frequency of salt tolerant efficiency in group A and B, it found that the death of plant responded to salt stress was divided into several phases in soybean population, and differences of soybean salt tolerance depended on which phase appeared earlier and remaining time.