Colchicine-Induced Double Haploid Production of Spring Bread Wheat (<em>Triticum</em> <em>aestivum </em>L.) via Wheat × Maize Hybridization

Bangladesh faces significant wheat grain deficiency compared to its demand due to the lengthy process (10-12 years) required to release a variety through a conventional breeding approach. Traditional breeding methods involve several years of various types of crosses between male and female parents and/or progenies, along with recurrent selection-crossing to obtain a homozygous line (F1 to F6 generations) with desired traits within almost 10 years. The double haploid (DH) method is also a time-saving, easier, and more reliable technique to achieve the desired traits in homozygous lines within 2-3 years. DH lines were produced by crossing two F1 hybrids of spring wheat with maize. 0.1% solution of colchicine was applied to produce DH of F2 progeny of wheat in the study. 80.8% (340) of the 421 pollinated florets from the two F1 wheat hybrids were produced as green parthenocarpic caryopses (GPCs) (F2). 35 of the 70 rescued embryos (or 20.6% of the GPCs) germinated. The germinated embryos regenerated 10 haploid green plants (14.3% of total embryos). After being applied colchicine, 8 of the regenerated haploid (H1) plants made it. Out of the 8 plants that made it through, only one developed homozygous double haploid seed (DH1 seed). These seeds were multiplied to produce DH2, used in the preliminary yield in the next year. The results demonstrated the potential of this method to produce a homozygous line within a short period (2-3 years) by doubling the haploid line generated through pollination of spring bread wheat F1 with maize.