Hybridisation between wheat and Aegilops geniculata and hybrid fertility for potential herbicide resistance transfer

Abstract

SummaryHybridisation between wheat and Aegilops geniculata was quantified in a 4‐year crossing experiment in the glasshouse, using three wheat cultivars as pollen donors and herbicide resistance as a phenotypic marker. Hybridisation rates ranged from 5% to 74%. Most of the hybrids were self‐sterile. However, seven F2 seeds were obtained from 165 A. geniculata–wheat hybrids. Hybrid seeds were found in all backcross (BC1) combinations at average rates of 4.2% (0–26.3%) and 5.88% (0–34%) under glasshouse and field experiments, respectively, with significant differences among years and cultivars. Wheat cultivars, F1 and BC1 plants, were resistant to herbicides while A. geniculata plants were susceptible. In the subsequent generations, although few plants were available, the BC1F1 had a certain degree of fertility and the fertility increased in the F2 plants, with one plant that reached 66.7%. The commercial growing of genetically modified herbicide‐tolerant wheat is expected to have the potential for the inserted gene to escape from the crop and become incorporated in a closely related wild species, conferring a competitive advantage to these conferring weeds. Determining the frequency of crop‐wild transgene flow and the fertility of the formed hybrids is a necessity for risk assessment. Data presented here provide new knowledge on the potential A. geniculata–wheat herbicide resistance transfer.