abstract
-
The dwarf-male-sterile (DMS) wheat (Triticum aestivum) was developed by crossing a natural mutation line Taigu with an artificial mutation line Aibian 1. Taigu carries gene MS2, a dominant gene conferring male sterility, and Aibian 1 carries gene Rht-D1c, a dominant gene conferring reduction of plant height. Both Ms2 and Rht-D1c are located on the short arm of chromosome 4D, and the percentage of recombination between the two genes is 0.18%. When the DMS wheat is crossed with any normal male fertile parents, there is always a clear cut of 1:1 segregation for dwarf male sterile plants and tall male fertile plants in the F1 generation. The dwarf male sterile plants can be used as a female parent in further hybridization, and the tall male fertile plants are advanced to pure lines to develop new varieties. We developed a DMS wheat breeding system, which includes the following steps: (1) development of a series of DMS wheat parental near-isogenic lines by backcrossing the DMS wheat with elite wheat parents; (2) establishment of a large-scale backcrossing population by crossing the DMS wheat parental near-isogenic lines to the cultivars or lines with the traits of interest; (3) application of marker-assisted selection for the major target genes; (4) induction of DMS double-haploid lines; and (5) application of the shuttle breeding approach for off-season trait evaluation. The strategy significantly increases the breeding efficiency and has a great potential in wheat breeding program.