Development and validation of diagnostic markers for the reduced height gene Rht8in wheat

Wheat (Triticum aestivumL.) 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. Rht8is a gibberellic acid–sensitive reduced height (Rht) gene and has been cloned. Rht8encodes 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 RNHLin wheat breeding. In this study, we found that different cultivars may carry 1–3 copies of RNHLson chromosome 2D, and only 2D carries the semi‐dwarf allele of RNHLalthough the wild‐type RNHLallele is detected in several other chromosomes. We developed two kompetitive allele specific PCR (KASP) markers, Rht8‐KASP‐V2and 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. Rht8has not been extensively deployed in US hard winter wheat and development of the diagnostic KASP markers will facilitate Rht8transfer to US wheat cultivars. Each cultivar carries 1–3 copies of ribonuclease H‐like domains (RNHLs) on 2D and mutations in all those copies determine Rht8phenotype.Two kompetitive allele‐specific PCR (KASP) markers were developed for the recently cloned Rht8gene.The two markers were diagnostic for Rht8in a wheat diversity panel.Low Rht8frequency in US wheat suggests high potential of using Rht8in the United States to improve US wheat production.