Researchers from China Agricultural University and the Chinese Academy of Agricultural Sciences have identified a new gene, Sdd1, that regulates plant height and spike architecture in bread wheat. This discovery offers breeders a fresh genetic tool to improve wheat traits without the common trade-offs associated with existing dwarfing genes. The gene, located on chromosome 3B, works by integrating multiple hormone signals, including gibberellin and auxin.
Modern wheat breeding has long relied on a narrow set of dwarfing genes to increase yield and prevent lodging. However, these traditional genes often limit seedling vigor or nitrogen-use efficiency. The AS34 mutant line studied by the team showed a 41.6% reduction in plant height and a 60.3% increase in spikelet density compared to standard wild-type wheat. Because Sdd1 functions independently of previously known genetic deletions, it allows scientists to stack traits more effectively.
The research team utilized fine-mapping and whole-genome resequencing to isolate the gene within a 5.7-Mb interval. By characterizing TraesCS3B02G260400 as the candidate for Sdd1, the study provides a clear target for future molecular breeding efforts. Professor Jie Liu and the research team note that this discovery allows for the design of wheat varieties that balance height reduction with productivity.
Ongoing work focuses on the specific molecular functions of the protein encoded by this gene. Understanding how it transmits hormonal signals will be key to applying this finding across diverse environmental conditions. This development marks a significant shift in the available toolbox for global crop improvement, aiming to move past the constraints of 20th-century Green Revolution genetics.