A diagnostic marker for the Hessian fly resistance gene H13 in wheat

Abstract

Hessian fly [HF; Mayetiola destructor (Say)] is a serious pest of wheat in the United States, and growing HF-resistant wheat cultivars is an effective approach to control the pest. H13 from Aegilops tauschii is a resistance gene on chromosome 6D that shows high resistance to multiple HF biotypes; however, diagnostic markers are not available for selection of the gene. This study developed two kompetitive allele-specific PCR (KASP) markers, Kasp_H13_R1064* and Kasp_H13_R217K, using the sequence of a previously reported H13 candidate gene. Both markers showed the same segregation pattern in a Molly × Newton population and 38 lines that carry different named HF resistance genes. The resistance marker alleles were detected in Molly (H13), KS89WGRC03 (H23), and KS89WGRC04 (Hwgrc4) with the resistance genes all mapped on chromosome arm 6DS from A. tauschii. The results suggest those markers are near diagnostic for all three HF resistance genes and they are either allelic or tightly linked. Kasp_H13_R1064* was validated in a diversity panel from the major US wheat-growing areas and three wheat lines carrying H13. Further screening of wheat breeding lines from 2022 hard winter wheat (HWW) regional nurseries (RGON2022 and RPN2022; where RGON is the Regional Germplasm Observation Nursery and RPN is the Regional Performance Nursery) with Kasp_H13_R1064* did not detect H13, suggesting that H13 has not been deployed in the current US HWW breeding programs. The resistance allele at Kasp_H13_R1064* was also relatively low (16.1%) in a worldwide A. tauschii collection. Development of the KASP marker for H13 will facilitate deployment of the gene in wheat breeding programs.