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

Abstract

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.