Effect of twenty four wheat genotypes on soil biochemical and microbial properties

Background and aims Understanding the effect of wheat genotype on soil properties will be crucial in breeding towards more sustainable wheat production and increased yield. We examined the relationships between root traits, soil properties and grain yield for 24 wheat genotypes grown under field conditions. Methods Wheat genotypes (Triticum spp.) with a range of different genetic backgrounds (varieties, breeding and synthetic lines) were planted in the field in northern NSW, Australia. Specific root length (SRL), root diameter (RD) and the proportion of root length in different diameter classes were characterized at the stem elongation growth stage. Soil microbial biomass carbon (MBC) and nitrogen (MBN), total dissolved nitrogen (TDN), organic nitrogen (DON), inorganic nitrogen (DIN), and soil bacterial community structure were measured. Results A significant wheat genotype effect was found for SRL, proportion of coarse roots (1-2 mm), MBN, MBC/MBN, TDN, and DIN. Genotypes with more fine roots generally had lower TDN, DIN and DON, higher MBN, and lower grain yield. We observed no wheat genotype effect on the structure and diversity of the soil bacterial community. Conclusions Long, thin wheat roots may promote microbial growth and N immobilisation, negatively affecting grain yield. We suggest that SRL, MBN and inorganic N should be considered by plant breeding schemes.