Calcium application synergizes lodging resistance and yield potential in rapeseed by cell wall strengthening and photosynthesis

Improving lodging resistance without compromising yield is a major challenge in rapeseed ( Brassica napus L.), a globally important oilseed crop. Here, we demonstrate that calcium application simultaneously enhances lodging resistance and yield of rapeseed under pot and field conditions. In pot studies, calcium treatment enhanced photosynthetic capacity, increased the number of siliques by an average of 29.4%, and improved thousand-seed weight, resulting in higher yields. Calcium treatment also increased stem bending resistance by altering stem structure and cell-wall composition, with upper- and lower-stem strength increasing by 33.0%–35.2% and 23.9%–30.6%, respectively. We confirmed these beneficial effects at multiple field sites with different soil types and planting densities. Physiological and biochemical analyses revealed that calcium treatment strengthens stem mechanical properties by promoting calcium pectate accumulation and reducing pectin methylesterification, as supported by the upregulation of pectin methylesterase ( PME ) genes. Furthermore, knockout of BnaPME35 abolished the effect of calcium treatment on lodging resistance, highlighting the role of pectin methylesterification levels in lodging susceptibility. These findings suggest that targeted application of calcium-containing fertilizers offers a practical strategy for improving lodging resistance and yield in rapeseed