Non-Mendelian inheritance of gene amplification-based resistance to glyphosate in Hordeum glaucum (barley grass) from South Australia

Abstract

Background: Hordeum glaucum Steud. is an important grass weed species in South Australia that has evolved resistance to glyphosate. This study investigated the mode of inheritance of glyphosate resistance in this species.

Results: Hand-pollination of glyphosate susceptible and resistant populations generated two F₁ individuals, selfed to yield F₂ progenies. In dose-response experiments, the F₂ progenies showed intermediate response between the two parent populations. High variation in EPSPS gene copies was observed among F₂ individuals, with some individuals possessing more gene copies than the resistant parent population. No evidence of a Mendelian single-gene pattern of inheritance was observed.

Conclusion: Inheritance of gene amplification in H. glaucum is non-Mendelian. © 2021 Society of Chemical Industry.

Keywords: EPSPS; copy number; gene amplification; glyphosate resistance; inheritance; non-Mendelian.