Breeding strategy for synergistic improvement of yield, disease resistance, and stress tolerance in Shumai 753 using the wheat landrace Xiaoganmai

The Sichuan wheat region is the most important early-maturing winter wheat production area in Southwest China, where increasing the number of effective spikes per unit area (i.e., spike capacity or effective tillers per plant) is key to further enhancing yield potential. The wheat landrace ‘Xiaoganmai’ from Dangyang, Hubei, exhibits stable resistance to stripe rust and pre-harvest sprouting, along with desirable agronomic traits such as multiple effective tillers and fertile spikelets, making it a promising genetic resource for wheat improvement and innovation in the Sichuan wheat region. Among yield components, the number of effective spikes per unit area has become the primary limiting factor for the breeding line ‘Shumai 753’. To optimize the yield structure of ‘Shumai 753’ by improving spike capacity through enhanced tillering, and to simultaneously improve yield, disease resistance, and stress tolerance by pyramiding genes for stripe rust and pre-harvest sprouting resistance, this study used progenies of ‘Xiaoganmai’—characterized by prolific tillering, strong resistance to pre-harvest sprouting, and adult-plant resistance to stripe rust—as donors, and ‘Shumai 753’—which harbors all-stage stripe rust resistance genes and exhibits favorable agronomic traits—as the recipient. Through hybridization, backcrossing, continuous multi-generational selfing, and a "segmented" target-trait selection strategy, 178 stable advanced-generation lines from the Shumai 753 × Xiaoganmai cross were developed. Phenotypic evaluations showed significant improvements in effective tiller number, grains per spike, and spikelets per spike in the derived lines compared to ‘Shumai 753’. All advanced lines exhibited more effective tillers than the recipient parent, with only four lines showing fewer spikelets, and the average grain number per spike exceeded 70. Correlation and path analysis of yield-related traits revealed that effective tiller number had a direct and highly significant positive effect on yield, indicating that using ‘Xiaoganmai’ to improve spike capacity is an effective strategy for enhancing the yield potential of ‘Shumai 753’. By integrating phenotypic and genotypic data, two breakthrough lines with yield potential exceeding 8250 kg hm-2 were identified. Additionally, genotyping for resistance loci revealed one line carrying Yr18+Yr24/26+Yr15, conferring broad-spectrum stripe rust resistance, and nine lines harboring TaMyb10 alleles associated with strong pre-harvest sprouting resistance. These findings demonstrate that utilizing the wheat landrace ‘Xiaoganmai’ in a segmented target-trait selection strategy provides a practical and effective approach for reconstructing the yield architecture of ‘Shumai 753’ and achieving synergistic improvements in yield, disease resistance, and stress tolerance in the Sichuan wheat region.