Maximizing grain yield requires a careful balance between photosynthesis, water use efficiency (WUE) and maintaining optimal leaf temperature for photosynthesis. Stomata are a key determinant in these processes as they regulate the balance of CO2 uptake for photosynthesis, while minimizing water loss and dehydration. Stomatal conductance is controlled both by anatomical features (such as density on the leaf) and functional response to environmental stimuli. Stomatal patterning and changes in aperture are independent but linked mechanisms whereby plants can optimize gas exchange to increase CO2 capture for photosynthesis, and to control water loss and leaf temperature through transpiration. This project targets different genes in stomatal development and functional pathways using transgenic/mutagenic approaches to improve photosynthesis and yield potential in wheat as part of a germplasm development initiative and to better characterise these pathways in cereals.