Effects on the yield and fiber quality components of Bt cotton inoculated with Azotobacter chroococcum under elevated CO₂

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 CO₂.

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 CO₂.

Results: The findings indicated that the inoculation of azotobacter significantly improved the yield and fiber quality components of Bt cotton, the elevated CO₂ 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 CO₂ 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 CO₂ in the future.