The Correlation Analysis of Selection Effect for SP_4 and Variations for SP_2 in Space Flight on Soybean

In order to definite the selection basis of agronomic traits for early generation and improve the selection effect in soybean space-mutation breeding. We analyzed the SP 2 generation variation rate and the SP 4 generation selection effects of six soybean varieties after space flight carrying. The results showed that the relationship between variation rate of pod and grain number per plant with high heritability of SP 2 generation and the selected plant number of SP 4 generation was extremely significant. While the relationship between variation rate of bottom pods height and internode length of SP 2 generation and selected plant number of SP 4 generation was significant. And the relationship among variation rate of plant height and pitch number of main stem of SP 2 generation and selected plant number of SP 4 generation was not significant. Therfore,the selection of SP 2 generation to pod number,grain number,bottom pods height,and internode length was effective,while the plant height and pitch number of main stem was not obvious.