Mitigation of soil water stress by moderately deep sowing and exogenous application of glucosinolates during the early seedling stage in rapeseed

Chenyang Bai¹Yizhong Lei¹Maria Batool¹Ali Mahmoud El-Badri¹Ying Chang¹Jie Kuai¹Bo Wang¹Jie Zhao¹Zhenghua Xu¹Sumera Anwar²Graham John King³Jing Wang^1*Guang Sheng Zhou¹

• ¹Huazhong Agricultural University, Wuhan, China
• ²Government College University Faisalabad, Faisalabad, Pakistan
• ³Southern Cross University, Lismore, Australia

Determining optimal sowing depth suitable for different water conditions is a key agronomic factor for crop establishment and yield potential. This study aimed to identify the optimal sowing depth for rapeseed that maximizes seedling vigour under varying water conditions. Seedling emergence and plant growth were observed under four water conditions (variable moisture, drought, normal water and waterlogged) at different sowing depths (1–5 cm). Meanwhile, The hypothesis that seedling vigour under deep sowing conditions could be improved by exogenous application of glucosinolates (GS) was tested. Results indicated that the highest seedling emergence percentage (EP) was observed at 3 cm, which was increased by 123.2% (variable moisture), 100% (drought) and 11.1% (normal water) than 1 cm. Under waterlogged stress seedling EP showed no significant differences between 1 and 3 cm for 50% of 16 cultivars. Moreover, seedling EP was significantly improved at 3 cm after seed priming by GS versus 1 cm, with increases of 46.4% (drought) and 63.0% (waterlogged), while no significant differences under normal water conditions. Furthermore, plant phenotypic performance indices were higher at 3 cm with GS treatment than 1 cm in all water conditions. Collectively, a sowing depth of 3 cm combined with exogenous application of GS not only promoted seedling emergence but benefited subsequent plant growth in direct-sown rapeseed. We expect our results to provide practical insights for ensuring reliable seedling establishment in rapeseed.