Production of herbicide-resistant jointed goatgrass (Aegilops cylindrica) x wheat (Triticum aestivum) hybrids in the field by natural hybridization

Imazamox-resistant hybrids resulted from a cross between jointed goatgrass and an imazamox-resistant wheat (cv. FS-4 IR wheat). Two imazamox-resistant hybrids were discovered in a research plot where FS-4 IR wheat seed had be en replanted from the harvest of an imazamox efficacy study conducted the y ear before at a different location. These hybrid plants survived imazamox a pplied at 0.053 and 0.063 kg ai ha(-1) in the field and produced seven viab le seeds (BC1). This seed germinated, and chromosomes were counted from the roots (2N number ranged from 39 to 54). In the greenhouse, six of the seve n plants survived an application of 0.072 kg ai ha(-1) imazamox, which conf irmed that the resistance trait had been passed to these progeny. A large a mount of phenotypic variation was observed in the mature BC1 plants. a gene tic description of the movement of the resistant gene is proposed based on the case of the gene being located on the D and the A or B genomes. Managem ent strategies to reduce the occurrence of herbicide-resistant hybrids are presented.