Effects on the yield and fiber quality components of Bt cotton inoculated with Azotobacter chroococcum under elevated CO.sub.2

Background The raising trend of cultivation of Bacillus thuringiensis (Bt)-transgenic cotton is faced with a new challenge what effects on the growth and yield of Bt cotton under elevated CO.sub.2 . Methods Rhizobacteria is the significant biological regulator to increase environmental suitability and ameliorate soil-nitrogen utilization efficiency of crops, especially Bt cotton. Pot-culture experiments investigated the effects on the yield and fiber quality components of Bt cotton (transgenic Line SCRC 37) inoculated with Azotobacter chroococcum (AC) under elevated CO.sub.2 . Results The findings indicated that the inoculation of azotobacter significantly improved the yield and fiber quality components of Bt cotton, the elevated CO.sub.2 significantly increased the soil density of A. chroococcum and the partial yield indexes (as cottonweightper 20 bolls, lint yield per 20 bolls and boll number per plant), and non-significant decrease the fiber quality components of Bt cotton except uniform. Discussion Overall results obviously depicted that the inoculation of azotobacter and the elevated CO.sub.2 had positive effects on the yield and fiber quality components of Bt cotton. Presumably, azotobacter inoculation can be used to stimulate plant soil-nitrogen uptake and promote plant growth for Bt cotton under elevated CO.sub.2 in the future.