Given that only 15% of the energy captured is translated into yield, improving how energy is used and distributed has the potential to increase growth and yield. Gaining a better understanding of the efficiency of plants with respect to mitochondrial dark respiration, and the proportion of this energy used to generate biomass and yield, has potential to inform breeding to improve wheat yields. Yield itself is a function of biomass and harvest index and biomass comprises of light intercepted and radiation use efficiency (RUE). The International Wheat Yield Partnership (IWYP) and Grains Research and Development Corporation (GRDC) project IWYP60 seeks to develop a new understanding of this energy use efficiency from multiple field trials and glasshouse based experiments. Data are integrated from very different sources, ranging from field physiology measurements, respiration and photosynthesis characterisation, through proteomics, metabolomics and genomics. One way to enhance RUE is to reduce maintenance respiration costs and one of the objectives of the study was look for genetic variation in rate of respiration at the vegetative stage in different wheat panels across three years. Field trials were conducted in Mexico at CIMMYT experimental research stations in Obregon in 2017 and 2018. Field trials were carried out at Ginninderra Experimental station (GES) in 2017 and 2018 on 30 Australian commercial varieties and on Seri-Babax (SBS) RIL population consisting of 177 lines. Wheat leaves were sampled at tillering and booting in each panel to measure dark respiration (Rd) and leaf reflectance measurements using hyperspectral ASD within 350-2500 nm wavelength was carried on same leaf prior to sampling for respiration. The remaining part of the same leaf was then frozen in liquid nitrogen for proteomics and metabolites analysis. A 2-fold variation was observed in 2017 and 2018 for PS Tails panel in Mexico and the respiration traits were found to be stable across the two years. A negative correlation was observed between grain yield and respiration traits for PS Tails panels. Similar findings were found for SBS panel.