College of Resources and Environmental Sciences Agricultural University 100193.R.China;
State Key Laboratory of North China Crop Improvement and Regulation/Mountain Area Research Institute Agricultural University 071001.R.China;
College of Resource and Environmental Sciences Agricultural University 830052.R.China;
Soil Biology Group University&Research 6700AA Netherlands;
cotton varieties; plant breeding; arbuscular mycorrhizal fungi; root economics space; OUTSOURCING; phosphorus acquisition;