Heat stress due to high ambient temperatures is a serious threat to crop production and productivity. To investigate the effect of salicylic acid foliar application on some phenological, morpho-physiological, and yield attributes of canola cultivars in two sowing dates, a field experiment carried out in a split plot factorial in randomized complete block design with three replications at Shahid Chamran University of Ahvaz in 2023-2024 growing season. Main plots consisted of two sowing dates; November 11, and December 11 (Normal and late sowing dates, respectively), and sub plot consisted of factorial arrangement of different concentrations of salicylic acid foliar application (0, and 200 μM), and canola cultivars (Hyola 4815, Agamax, Hyola50, and Trapper). The interaction between sowing date, hormone foliar application, and cultivars significantly affected the number of pods per plant, seed yield, oil yield, stomatal conductance, and chlorophyll index. Heat stress in late sowing date caused a significant decrease in all traits, but salicylic acid enhanced traits in both sowing dates. Late sowing caused a 28% reduction in seed yield. In late sowing date, foliar application of salicylic acid enhanced seed yield by 4, 29, 35, and 28%, in Hyola 4815, Agamax, Hyola50, and Trapper cultivars respectively, when compared to salicylic acid-deficient plants. Agamax, Trapper, and Hayola 50 along with 200 μM salicylic acid foliar application showed the highest seed and oil yield in both sowing dates. Overall, salicylic acid foliar application mitigated the negative effects of heat stress by improving morpho-physiological traits and seed and oil yields.
|
