Double Haploids in Marker-Assisted Gene Introgression in Wheat (Triticum aestivum L.)

Double haploid (DH) technique is used to generate completely homozygous plants in a single generation. Microspore culture is the method of production of DHs from immature pollens by androgenesis. Success of this technique is determined by genotype, health of donor plant and growth conditions; correct staging of microspores, pretreatment methods, and regeneration media. The objectives of this study are (i) establishment of microspore culture-based DH technique, (ii) introgression of multiple genes following Marker-Assisted Selection (MAS); and (iii) utilization of DH technique to fix the introgressed genes at homozygous condition in a single generation. Immature pollens at mid to late uninucleate stage were used to generate DHs. Conventional hybridization between the parents carrying the selected genes for desired traits (resistance to stem, leaf and yellow rust; grain protein content) was used to develop F₁ hybrids. MAS was used to identify DHs carrying the desired genes at homozygous condition. We have standardized the optimal growth conditions for donor plants and correct growth stage of spikes. Microspore culture to generate DHs using the selected F₁ hybrids and MAS for identifying the DHs carrying the desired genes are in progress. The selected lines will be multiplied and tested in field trials for yield and other agronomic performances. Microspore culture has advantages over other DH techniques in generating large numbers of DHs from limited F₁ hybrid plants. This approach for introgression of multiple genes applying DH-MAS has potential to develop improved wheat parent lines/cultivars faster and more precisely compared to the conventional breeding system.