Ugrin, Josey M.Hogg, Andrew C.Tracy, Emma M.Tillet, Brandon J.Cook, Jason P.Martin, John M.Giroux, Michael J.2024-01-092024-01-092023-10Ugrin, J. M., Hogg, A. C., Tracy, E. M., Tillett, B. J., Cook, J. P., Martin, J. M., & Giroux, M. J. (2023). Dosage response to reduced height‐1 (Rht‐1) loss‐of‐function mutations and characterization of slender phenotype in hexaploid wheat. Crop Science, 63(6), 3457-3469.0011-183Xhttps://scholarworks.montana.edu/handle/1/18264This is the peer reviewed version of the following article: [Dosage response to reduced height‐1 (Rht‐1) loss‐of‐function mutations and characterization of slender phenotype in hexaploid wheat. Crop Science 63, 6 p3457-3469 (2023)], which has been published in final form at https://doi.org/10.1002/csc2.21116. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions: https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html#3.The reduced height (Rht-1) genes in wheat (Triticum aestivum L.) are integral in controlling plant height. Previous studies in other plant species have demonstrated that loss-of-function mutations in their orthologous Rht-1 genes results in plants with a slender phenotype illustrated by increased plant heights, sterility, and a constitutive gibberellic acid (GA3) response; however, this phenotype has not been described in wheat. In this study, nonsense alleles occurring in the GRAS domain of Rht-A1, B1, and D1 were combined to create single, double, and triple Rht-1 mutants. Homozygous lines possessing none, one, two, or three Rht-1 stop mutations were grown in replicated field trials in three environments to assess agronomic traits. Germination tests to measure GA3 responsiveness and gene expression analysis via RNA-seq were also performed. Rht-1 triple mutants exhibited a slender phenotype characterized by rapid growth, elongated coleoptiles and internodes, elongated spikes, decreased tiller and spikelet number, and sterile heads. The presence of a single functional Rht-1 gene resulted in a normal phenotype. Differences in plant height among the Rht-1 double mutants, Rht-1 single mutants, and Rht-1 all wild-type dosages trended toward increased plant height with increased Rht-1 stop mutation dosage. Differences in Rht-1 homeolog gene expression did not equate to differences in plant height between the different Rht-1 stop mutations.en-UScopyright Wiley 2023https://www.wiley.com/en-us/permissionsdosage responseloss-of-functionmutationsslender phenotypehexaploid wheatArticle