High Night Temperature Exposure Alters Physiological and Bio-Chemical Parameters Affecting Pod Yield and Oil Quality in Canola.

Canola (Brassica napus L.) is an economically valuable oilseed crop. Winter-grown canola production is adversely affected by several environmental factors, but more importantly by high temperature stress. Multiple independent analysis of long-term weather data has revealed that minimum night-time temperature is increasing at a more rapid pace compared to maximum day- time temperature at farm, regional and at global scale. Hence, the major objective of this research was to investigate the effect of high night temperature (HNT) during flowering and pod filling stages and its’ impact on the physiological and bio-chemical parameters affecting yield parameters, protein and oil composition in winter canola. An experiment involving ten canola cultivars was conducted in climate-controlled environment chambers following a split-plot design. The cultivars were grown under day/ night temperatures of 23/15 °C (control), then exposed to HNT of 23/20 °C from early flowering till physiological maturity. Time-of-day-of-flowering at hourly intervals were recorded for three consecutive flowering days under both control and HNT treatments. Photochemical efficiency of PSII, thylakoid membrane damage and chlorophyll concentration on the 7^th and 14^th day of HNT treatment were measured. Pods obtained at harvest were used for quantifying grain quality (protein and oil) and other yield and biomass traits. Contrasting lines selected based on HNT response are currently being validated and will be discussed towards developing winter canola with enhance resilience to HNT exposure under future warming scenarios.