Reciprocal Evaluation of Hybrid Wheat (Triticum aestivum L.) Crosses Between German and US ‘Great Plains’ Genotypes Across Their Contrasting Target Environments

Hybrid wheat could deliver the grain yield (GY) and stability levels to confront climate change while crossing genetically divergent pools should maximize heterosis. We crossed 22 breeding lines from Nebraska (USA) with two German cultivars to produce 44 hybrids. Hybrids, parents and 12 checks were reciprocally tested across their contrasting target environments for GY, plant height and flowering biology during 2 consecutive years at multiple locations. Trait variation within target environments had the greatest impact on performance. Therefore, mega‐environments could not be derived from target environments despite a clear clustering using weather variables. Short plants and locally optimized flowering biology were main drivers for crop performance and adaptation. Modified Rogers' distances derived from genotyping‐by‐sequencing revealed the genetic divergence between German and ‘Great Plains’ pools. However, variation on GY heterosis could not be explained by this divergence. In general, GY of hybrids was more stable across target environments than for locally adapted material, whereas GY heterosis was higher under harsh climate conditions of the Nebraska's ‘Great Plains’.