The Association of Yield Stability With Epicuticular Leaf Wax Across Diverse Environments.

Wheat (Triticum aestivum) yields may fluctuate across environments due to genotype by environmental interactions. Abiotic stresses such as water deficit and high temperature are two major adverse factors that affect yield and end-use quality stability. Epicuticular wax load (EWL) reduces canopy temperature and improve yield by reducing transpiration and the amount of light entering the leaf. Selecting for stability across locations, particularly in environments with low ground water or high temperature, may be a useful method of selecting for stress tolerance. The goal of this study was to identify associations between stable yield and leaf epicuticular wax load. To identify these associations, canopy temperature, epicuticular wax and yield data were collected. A 180 recombinant inbred line (RIL) population, created from the cross of ‘Halberd’, an Australian high temperature tolerant cultivar and ‘Len’, a North Dakotan cultivar, was used. The population was grown in four locations in 2011; three in Texas and one in Mexico. Two Texas locations were used in 2012. Results show that plot yield correlated with leaf epicuticular wax load and canopy temperature, indicating that epicuticular wax load plays a role in yield and end-use quality stability. Leaf epicuticular wax load was significantly higher in water deficit conditions compared to irrigated conditions. In fact, the environment with the highest temperature resulted in the highest leaf EWL. As a result of this, a few lines were identified as stable in diverse environments and can be used in future breeding.