Identification of genetic factors regulating anther size in wheat under heat stress environment.

Wheat is a vital global crop, essential for food security, yet its productivity is increasingly threatened by rising temperatures, particularly during critical reproductive stages. This study investigates the genetic basis of anther size, a key reproductive trait, in response to heat stress, using a diverse panel of 177 historical wheat cultivars. High heritability and genetic advance were observed for anther size traits, indicating strong genetic control and potential for breeding improvements. Genome-wide association studies (GWAS) identified 121 significant genetic loci associated with anther length and width under both normal and heat-stressed environments. Under heat stress environment 19 and 18 loci were identified for anther length and width, respectively. Of which, three and one loci for anther length and width, respectively, were found common in both years. Additionally, two pleiotropic loci on chromosomes 4B, and 6A were identified. For these important loci, eight genes were annotated as putative candidate genes for anther size under heat stress. Transcriptome and relative expression profiling of these candidate genes revealed the differential expression pattern of the two candidate genes. Notably, these candidate genes i.e., Expansin (TraesCS1A01G300200.1), and Pollen proteins Ole e I-like (TraesCS6A01G103600.1) might have key role in maintaining the anther size under heat stress. These findings provide valuable insights into the genetic mechanisms underlying heat stress resilience in wheat by maintaining the spike fertility. However, further functional validation of these candidate genes are required to utilize them for improving terminal heat stress tolerance in wheat.