Field experiments combined with RNA sequencing revealed that wheat ploidy influences heat stress resilience, with tetraploid T. turgidum showing the smallest yield loss and hexaploid T. aestivum mounting the largest transcriptional response. Ploidy-dependent differences were observed in differential gene expression, alternative splicing—including hexaploid-specific exon skipping of NF‑YB—and co‑expression networks linked to grain traits, highlighting candidate pathways for breeding heat‑tolerant wheat.