Genetic and Physiological Responses of Sunflower to Nitrogen Availability: Implications for Sustainable Agriculture

Sunflower is an important crop for farmers and consumers.A field experiment (RCBD, three biological replicates) at the College of Agriculture -University of Baghdad evaluated two genotypes (Ishaqi1, Ishaqi2) under four nitrogen rates (0, 100, 200, 300 kg N ha-1).Morphological and yield traits were recorded and expression of gene AY941250 at flowering was measured by RT-qPCR using 18S rRNA for normalization.MIQE-compliant validation of the qPCR assay (primer specificity, efficiency, melt curves, and reference gene assessment) is provided in Methods and Supplementary Materials.Results show that higher N was associated with increased plant growth, yield components and higher AY941250 transcript levels in both genotypes; Ishaqi1 displayed the largest fold increase under the highest N.These findings are associative: they document correlation between N supply and AY941250 expression but do not establish causation.Functional confirmation (e.g., gene knockdown/overexpression and independent qPCR validation) is required to determine the gene's role in nitrogen uptake or use efficiency.