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Wheat (Triticum aestivum L.) production is necessary for global food and nutrition security. Reducing plant height is an effective strategy to increase lodging resistance, harvest index, and eventually wheat yield. Rht8 is a gibberellic acid–sensitive reduced height (Rht) gene and has been cloned. Rht8 encodes a ribonuclease H‐like (RNHL) superfamily protein that reduces plant height without reduction in coleoptile length. High‐throughput diagnostic markers are not available for precise selection of RNHL in wheat breeding. In this study, we found that different cultivars may carry 1–3 copies of RNHLs on chromosome 2D, and only 2D carries the semi‐dwarf allele of RNHL although the wild‐type RNHL allele is detected in several other chromosomes. We developed two kompetitive allele specific PCR (KASP) markers, Rht8‐KASP‐V2 and Rht8‐KASP‐V3, based on the causal variation in RNHL. The two markers co‐segregated with plant height in a recombinant inbred population and were validated in a panel of hard winter wheat breeding lines from the 2022 Regional Germplasm Observation Nursery and Regional Performance Nursery. Rht8 has not been extensively deployed in US hard winter wheat and development of the diagnostic KASP markers will facilitate Rht8 transfer to US wheat cultivars. Core Ideas: Each cultivar carries 1–3 copies of ribonuclease H‐like domains (RNHLs) on 2D and mutations in all those copies determine Rht8 phenotype.Two kompetitive allele‐specific PCR (KASP) markers were developed for the recently cloned Rht8 gene.The two markers were diagnostic for Rht8 in a wheat diversity panel.Low Rht8 frequency in US wheat suggests high potential of using Rht8 in the United States to improve US wheat production. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) wild relatives are rich genetic resources for genetic improvement of wheat. The short arm of rye (Secale cereale L.) chromosome 1 (1RS) contains many beneficial genes for resistance to drought, insects, and diseases, therefore the 1RS wheat translocations have been widely used in wheat breeding programs worldwide. To facilitate marker‐assisted identification of 1RS in wheat breeding, we designed a set of Kompetitive allele‐specific polymerase chain reaction (KASP) markers to detect the translocations of 1RS with long arm from wheat chromosome 1A (1RS.1AL) and 1RS with long arm from wheat chromosome 1B (1RS.1BL) based on the sequence flanking single nucleotide polymorphisms (SNPs) generated by genotyping‐by‐sequencing (GBS) between wheat and rye panels. We identified a set of three SNP markers for diagnosis and differentiation of the two 1RS translocations in wheat. Among the three KASP markers, 1AS‐05056 is 1RS specific, and clearly separated the genotypes with 1RS (1RS.1AL and 1RS.1BL) from those without the two 1RS translocations; whereas 1AS‐29875 clearly identified the 1RS.1AL translocation and 1BS‐16654 separated 1RS.1BL from 1RS.1AL. The three new KASP markers together accurately identified the presence of 1RS translocation on either 1A or 1B chromosome in a panel of 95 representative U.S. winter wheat accessions, which were further validated in two additional U.S. hard winter wheat panels. Therefore, they can be used for routine screening of 1RS.1BL and 1RS.1AL translocation lines in wheat breeding programs. Core Ideas: 1RS, 1AS, and 1BS specific SNPs were identified by analyzing GBS‐SNPs from both wheat and rye panels.Three chromosome‐arm‐specific KASPs clearly detected the 1RS.1AL and 1RS.1BL translocations in wheat.Three KASP markers were diagnostic for 1RS.1AL and 1RS.1BL in two U.S. hard winter wheat panels. [ABSTRACT FROM AUTHOR]