Development of doubled haploid lines in spring wheat (Triticum aestivum L.) through wheat × maize hybridization and...

Bangladesh faces a significant deficit in wheat grain production relative to its national demand, largely due to the prolonged duration-typically 10 to 12 years-required to release a new variety through conventional breeding approaches. Traditional methods involve multiple years of crossing between male and female parents or their progenies, followed by recurrent selection to develop homozygous lines (from the F1 to F6 generations) possessing desired traits. In contrast, the doubled haploid (DH) method offers a faster, simpler, and more reliable alternative, enabling the development of homozygous lines within just 2-3 years. In this study, DH lines were produced by crossing two F1 wheat hybrids with maize. A 0.1 % colchicine solution was applied to induce chromosome doubling in the F₂ progeny. Of the 421 florets pollinated, 340 (80.8 %) developed into green parthenocarpic caryopses (GPC). From these, 70 embryos (20.6 %) were successfully rescued, and 35 (50 %) of the rescued embryos germinated. Ten green haploid plants (28.6 % of the germinated embryos) were regenerated and subsequently transplanted. After colchicine treatment of nine haploid (H₁) plants, eight (88.9 %) survived. Among them, one plant (12.5 %) successfully produced homozygous doubled haploid (DH₁) seed. These seeds were then multiplied to obtain DH₂ seeds, which were evaluated in a preliminary yield trial next year. The results confirm the effectiveness of this method in generating homozygous lines within a significantly shorter time frame (2-3 years) by utilizing maize pollination and colchicine-induced chromosome doubling.