Determining the Pollen Parent of Field-Grown Backcross Progenies of Wheat ( L.) × Jointed Goatgrass ( Host) Hybrids Using Genomic In Situ Hybridization (GISH)

Jointed goatgrass (Aegilops cylindrica Host) with CCDD genomes is a noxious weed of winter wheat (Triticum aestivum L.) Wheat (BBAADD) and jointed goatgrass (JGG) can hybridize under natural conditions, leading to a possibility of gene flow between these two species. For a gene to move from herbicide-resistant wheat to JGG, JGG must be the recurrent parent in a series (two) of backcrosses. One way of determining the pollen parent in the first backcross is to visualize C-genome chromosomes using genomic in situ hybridization (GISH). By using GISH it was determined that 7 of 88 (8%) BC1 plants had more than seven C-genome chromosomes, indicating that JGG was the pollen parent. By using wheat-specific chloroplast simple sequence repeat marker (WCt-3) analysis, 13.6% of the hybrids had wheat as the female parent, while the remaining plants had JGG as the female parent. This study presents a reliable way of determining the pollen parent of BC1 progeny and the hybridization dynamics between wheat and jointed goatgrass under natural field conditions This information can be used to more accurately predict the risk for gene migration between wheat and jointed goatgrass.