Exploring eco‐evolutionary and temporal patterns of arbuscular mycorrhizal fungal communities colonizing <scp> <i>Sorghum bicolor</i> </scp> across sites of contrasting land use history and climate

Societal Impact Statement Sorghum bicolor is a globally important cereal crop with annual yields exceeding 50 million tons across more than 100 countries and can be grown on marginal lands where conventional agriculture is limited. We examined how eight genetically diverse sorghum genotypes shaped arbuscular mycorrhizal fungal (AMF) community assembly across two contrasting field environments. We found that sorghum genotype influences AMF community composition and that this showed a pattern over time. These findings suggest that crop genotype selection can be a useful practical tool to modulate root‐microbial interactions in low‐input and marginal agricultural systems, with implications for sustainable intensification strategies and microbiome‐informed crop breeding programs. Summary Arbuscular mycorrhizal fungal (AMF) symbiosis can influence crop production but can be variable across environmental conditions, host‐partner complementarity, and temporal dynamics. Understanding how these factors interact to shape AMF community assembly allows for the selection of crop genotypes that may maximally utilize AMF associations in agricultural systems. We assessed the development of AMF communities colonizing the roots of eight genetically diverse genotypes of Sorghum bicolor across a growing season. We used two field sites with contrasting environments and management histories. Sorghum cultivated in Georgia (GA) sorghum harbored 3.7‐fold more species than Arizona (AZ). We observed evidence of host‐filtering of AMF communities, with genotypes displaying more distinct associations in GA than AZ. AZ showed rapid shifts from early Funneliformis mosseae dominance to increasing dominance by either Entrophospora etunicata or Diversispora aurantia . In GA, we observed temporal variation associated with turnover of low‐abundance taxa contributing to larger family‐level patterns. Our findings demonstrate that there is potential for leveraging intra‐species genetic variation in AMF community assembly as an extended plant phenotype.