Remobilization of stem water-soluble carbohydrate (WSC) during grain filling has been found to contribute to enhance potential kernel size especially in dryland areas. A study testing 36 diverse genotypes was established to assess genotypic variation for stem storage capacity and its relationship with yield under two contrasting environments (drought and irrigated). The hypothesis that the width of internodes and solid stems contribute to a higher accumulation of stem reserves was also tested. The ultimate goal was to identify morphological traits that contribute to improve grain yield with potential use for wheat breeding. Stem samples were taken both at early grain filling and maturity. Stem parameters such as length, internode number and length, and internode width were measured. Dried and ground samples were scanned for WSC with a NIRSystem 6500. Changes in stem morphology were reported for the different environments and they were related to yield performance. Yield variation is discussed emphasizing differences between solid and hollow-stemmed wheats. Implications for breeding for high stem reserve genotypes are discussed.