Ameliorating thermo-tolerance in bell pepper (Capsicum annuum L. var. grossum) with plant growth regulators

Extreme temperatures have always been a serious threat to bell pepper production owing to its heat sensitivity. The present investigation was planned to assess the effect of foliar spray of growth regulators on morpho-physiological and yield parameters in bell pepper cv. Royal Wonder. Spraying bell pepper with Salicylic Acid (SA) and 24- Epibrassinolide (EBR) solutions significantly improved their tolerance to subsequent high temperatures. Exogenous application of three different concentrations of growth regulators i.e SA (0.10 mM, 0.20 mM and 0.50 mM) and EBR (0.05 μM, 0.10 μM and 0.20 μM) were applied at following stages; 30 days after transplantation (DAT), 60 DAT and 90 DAT. These treatments helped in mitigating the heat stress by improving growth parameters (plant height, plant spread and leaf area), photosynthetic efficiency, membrane thermostability, pollen viability and fruit set percent even at high temperature shows that application of PGRs definitely plays a role in initiating various mechanisms involved in overcoming high temperature limitations. However, foliar application of 0.20 mM SA (30 DAT) followed by 0.10 μM EBR (60 DAT) significantly enhanced the growth and yield parameters as compared to untreated control.