Pollen‐Mediated Gene Flow in Wheat at the Commercial Scale

ABSTRACT Currently, information is lacking on gene flow in common wheat (Triticum aestivum L.) at distances greater than 300 m based on commercial‐scale fields. The objective of this research was to measure pollen‐mediated gene flow rates from a blue‐aleuroned pollinator (T. aestivum cv. ‘Purendo‐38’) to neighboring commercial fields of common wheat grown within a 10‐km radius of a central pollinator field. In the 2‐yr study, 33‐ha (2002) and 20‐ha (2003) fields of Purendo‐38 were sown 200 km east‐northeast of Saskatoon, Saskatchewan. Sixty‐nine fields in 2002 and 76 fields in 2003 were identified as having overlapping flowering relative to Purendo‐38. At maturity, up to 2 m2 samples were harvested from each corner of each recipient field. Gene flow was identified by the expression of a light‐blue pigment in the aleurone layer of F1 hybrid seed. In 2002 one case of gene flow was confirmed at 190 m northeast of the pollinator at a rate of 0.01%. In 2003 nine putative hybrid seeds were confirmed to be the result of gene flow between Purendo‐38 and the recipient field using gliadin fingerprinting. Consequently, gene flow was confirmed at 0.01% at 500 m northeast, 630 m southeast, and 2.75 km northwest from the pollinator. In commercial production, gene flow in wheat occurs at trace levels (≤ 0.01%) at distances up to 2.75 km.