Hello Yousaf, I have some of the papers you sent me. However, I don't think that research focus on traits that I mentionned above (I mean leaf transpiration rate, photosynthesis rate and stomata conductance rate). Here we use CI340 photosynthesis system tool to measure these traits with many difficulties even in a normal size breeding trial. So I want to develop VI based prediction models to estimate but wich proxy is appropriate? that's the BIG QUESTION