Potential for gene flow between wheat (Triticum aestivum) and jointed goatgrass (Aegilops cylindrica) in the field

Aegilops cylindrica is a major weed in the wheat producing areas of the wes tern United States. One method proposed to control Aegilops cylindrica is t he use of herbicide resistant wheat. Of concern is whether a herbicide resi stance gene could be transferred from wheat to Aegilops cylindrica. Aegilop s cylindrica shares the D genome with wheat and interspecific hybrids betwe en the two species occur in the field. In previous greenhouse research, par tial self-fertility was restored in the BC, generation after backcrossing t o Aegilops cylindrica. The objective of this research was to determine if b ackcrossing of the wheat x Aegilops cylindrica hybrid could occur in the fi eld. Hybrids were transplanted with various combinations of wheat and Aegil ops cylindrica plants. Field derived BC, plants were transplanted into stan ds of Aegilops cylindrica. Both BC, and BC, seeds were produced in the fiel d by natural backcrossing. Seed harvested off the hybrid plants had a high germination rate. Four BC, plants were found to be partially self-fertile. The production of BC, seed in the field and the low level of self-fertility of BC, plants indicates that hybrids could serve as a bridge in the transf er of genes between wheat and Aegilops cylindrica in the field. Any release of a herbicide resistant wheat should be accompanied by a management plan that would minimize the potential for gene movement between these species.