[Objective] The aim of this study was to investigate the effect of space flight factors on plant biomass in the generation of alfalfa carried by the satellite.[Method]Seeds from three lines of alfalfa were carried by the seed-breeding satellite Shijian-8.After the satellite returned to the ground,stem diameter,primary branch number and current-year individual biomass of alfalfa were studied.[Result]After space flight,primary branch number and current-year individual biomass of alfalfa increased significantly,while the stem diameter had no significant change.Using the value over(the mean value of control + three standard deviation)as a criterion to screen,the variants with enlarged stem diameter,increased primary branch number and individual biomass was two,five and twelve respectively.[Conclusion]The obtained variants can be used in the variety improvement of alfalfa and its new variety breeding,but whether its favorable variation can inherit stably to the progenies needs further study.
[Objective] The study aimed to understand the mutagenic effects of space flight on alfalfa seeds.[Method] Seeds of three lines of alfalfa were carried into orbit by the satellite 'Shijian-8' for space fight,the indices including seed germination rate,plant height and growth rate,were measured after the seeds been retrieved.[Result] Remarkable mutagenic effects occurred on the flight seeds,which were mainly presented by abnormal cotyledon,extended variation range of plant height and growth rate.Nineteen plants with increased plant height were preliminarily screened from the T0 progenies,but whether the mutated trait could inherit should be confirmed in further study.Three flight lines of alfalfa are different in the percentages of abnormal cotyledon(10%-18%),variation range of plant height(increased 30%-150% compared to control),selected plant number with increased plant height(5-7 plants),suggesting that differences exits between the three lines in mutation efficiency.[Conclusion] Valuable mutated materials could be obtained by space flight and applied in modern agriculture.
