Abstract

To investigate the effect of space flight factors on lespedeza seeds, dry seeds ofLespedeza bicolor were loaded into recoverable satellite for space flight in 2003. After the retrieval, key agronomic traits were tested. Among the 65 plants we tested in the first generation (SP1), ten plants showed changed phenotype characters as prematurity, late-maturity, tall, dwarf, multi-ramify and etiolation. The mutation rate varied from 1.5 to 4.6% among different traits. 60 primers were screened in RAPD analysis to evaluate DNA variation between mutations and their ground controls. Results showed that 272 amplified bands produced by 55 primers. Among them, 12 primers amplified 41 polymorphic bands. Pattern of bands showed that absence of common bands were observed in mutated plants compared with the ground control. Moreover, similar band pattern was observed in the same mutation phenotype. Conclusion was that space flight factors could induce inheritable mutagenic changes on bush clover seeds, and verified these changes in genetic material in the mutants. These mutations may due to the breakage of chromosome fragments which was induced by complex traits of space flight, especially the cosmic radiation and microgravity. More work is being conducted to select the stable mutants with favorable traits and used them in developing new cultivars.

Key words: Lespedeza bicolor, spaceflight, RAPD.