Mitigation of drought damage to rapeseed (Brassica napus L.) from sprays of film antitranspirants at different concentrations.
Xiang, J. (2022) Mitigation of drought damage to rapeseed (Brassica napus L.) from sprays of film antitranspirants at different concentrations. Doctoral thesis, Harper Adams University.
|
Text
Jie Xiang_PhD thesis_final.pdf Download (3MB) | Preview |
Abstract
Drought causes massive yield losses in rapeseed (Brassica napus), particularly during flowering when crops are most sensitive to water stress. It has been shown that film antitranspirant (AT) can effectively improve the yield of droughted rapeseed if applied at the flowering stage, yet the mechanism by which film AT mitigates drought damage and the concentration-response relationship between AT and crop yield remain unclear. To understand the underlying physiological mechanism and determine the optimum concentration of AT for rapeseed, the following experiments were conducted: five experiments measuring leaf coverage; three experiments imposing a short-term controlled drought during the flowering stage in the glasshouse; two experiments imposing a terminal drought in the field under polytunnels. Results showed that AT application at the early flowering stage decreased stomatal conductance more than photosynthesis of rapeseed, which improved intrinsic water use efficiency under both drought conditions. This suppression of gas exchange was positively correlated with AT concentrations due to changes in leaf coverage. However, yield responses to AT were only observed when rapeseed was under terminal drought, with increasing AT concentrations resulting in higher yields. Across concentrations and two sites, AT increased seed yield by 24%, predominantly from pod number increases compared to droughted control. Rapeseed treated with 3% AT produced the highest seed yield by 37% over unsprayed droughted plots, with about 31% adaxial leaf coverage. Pod number and leaf relative water content were positively correlated. It was concluded that yield benefits from AT application might be mediated by improving leaf water status to sustain rapeseed pod formation, and a greater yield can be achieved by increasing AT concentrations with conventional spraying on the adaxial surface. Therefore, the interactive effects of drought with AT concentrations and developing a cost effective spraying method by also covering the abaxial leaf surface would merit further investigation.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Divisions: | Agriculture and Environment (from 1.08.20) |
| Depositing User: | Miss Terésa-Marie Jones |
| Date Deposited: | 12 Apr 2023 15:32 |
| Last Modified: | 12 Apr 2023 15:32 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/17935 |
Actions (login required)
 |
Edit Item |