Hybridization in a Commercial Production Field between Imidazolinone-Resistant Winter Wheat and Jointed Goatgrass (Aegilops cylindrica) Results in Pollen-Mediated Gene Flow of Imi1

• Published in: Weed science 2010-10, Vol.58 (4), p.395-401
• Main Authors: Perez-Jones, Alejandro, Martins, Bianca A. B., Mallory-Smith, Carol A.
• Format: Article
• Language: English
• Subjects: Aegilops cylindrica; Agronomy. Soil science and plant productions; backcrossing; Biological and medical sciences; Chemical control; Chloroplasts; Chromosomes; fallow; Fundamental and applied biological sciences. Psychology; Gene flow; Genetic hybridization; genetic resistance; Genomes; grass weeds; herbicide resistance; herbicide-resistant acetohydroxyacid synthase (AHAS); Herbicides; Hybridity; imazamox; intergeneric hybridization; interspecific hybridization; introgression; mortality; natural hybridization; Parasitic plants. Weeds; parentage analysis; Phytopathology. Animal pests. Plant and forest protection; Plants; pollen; pollination; Polymerase chain reaction; seed germination; seed set; transgenic plants; Triticum aestivum; WEED BIOLOGY AND ECOLOGY; Weeds; Wheat
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1614/WS-D-10-00027.1

Imidazolinone-resistant (IR) winter wheat allows selective control of jointed goatgrass with the herbicide imazamox. However, the spontaneous hybridization between jointed goatgrass and IR winter wheat threatens the value of the IR technology. The objectives of this study were to determine if F1 hybrids collected in a commercial production field under IR winter wheat–fallow rotation in Oregon and their first-backcross progeny (BC1) carried the Imi1 gene and were resistant to imazamox, and to analyze the parentage of F1 and BC1 plants. The average seed set of the F1 spikes was 3.3%, and the average germination of BC1 seed was 52%. All F1 and BC1 plants tested carried Imi1. Jointed goatgrass plant mortality was 100% when treated with imazamox at 0.053 kg ai ha−1, compared to 0% for IR winter wheat and BC1 progeny. All F1 plants had jointed goatgrass as the maternal parent; whereas, most BC1 plants (85.7%) were produced with IR winter wheat as the paternal backcross parent. Although the backcrossing of F1 hybrids with jointed goatgrass is very low, it demonstrates the potential for introgression of Imi1 from IR winter wheat into jointed goatgrass under natural field conditions.