Exogenous 24-Epibrassinolide (24-EBL) Enhances Morpho-physiological Traits in Wheat (Triticum aestivum L.) Genotypes under High Temperature Stress
Gali Suresh
Department of Botany and Plant Physiology, Chaudhary Charan Singh Haryana Agricultural University (CCS HAU), Hisar 125004, India.
Priyanka Sharma *
Department of Crop Physiology, Assam Agricultural University (AAU), Jorhat 785013, Assam, India.
Pravin Prakash
Department of Plant Physiology, Institute of Agricultural Sciences, Banaras Hindu University (BHU), Varanasi 221 005, Uttar Pradesh, India.
Basant Kumar Dadrwal
Department of Plant Physiology, Sri Karan Narendra Agriculture University, Jobner 302024, Rajasthan, India.
Asha Kumari
ICAR-Indian Agricultural Research Institute (ICAR-IARI), Gauria karma, Hazaribagh 825405, Jharkhand, India.
Madisetty Sai Venkata Ravi Teja
Department of Crop Physiology, University of Agricultural Sciences (GKVK), Bengaluru 560065, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
High temperature stress is one of the major constraints limiting wheat (Triticum aestivum L.) productivity worldwide. Brassinosteroids (BRs), a class of plant steroidal hormones, play a pivotal role in modulating plant growth and conferring tolerance to various abiotic stresses. The present study aimed to investigate the effects of foliar-applied 24-epibrassinolide (24-EBL) on morpho-physiological traits of heat-tolerant (HUW-510) and heat-susceptible (HUW-468) wheat genotypes grown under field conditions during the Rabi season of 2017–18. Treatments included three concentrations of 24-EBL (0.01, 0.02, and 0.03 mM) and a control, applied at pre-flowering (40 DAS) and post-flowering (65 DAS) stages. Morpho-physiological parameters were assessed at two critical growth stages, i.e., 65 and 85 days after sowing (DAS). Results revealed that 24-EBL significantly improved root length, shoot height, leaf number, leaf area, total dry weight, relative water content (RWC), and membrane stability index (MSI) compared to untreated control plants exposed to heat stress. Among the concentrations tested, 0.02 mM 24-EBL proved most effective in sustaining growth and physiological integrity. Furthermore, the tolerant genotype HUW-510 exhibited higher responsiveness than HUW-468 suggesting genotypic differences in BR-mediated thermotolerance. The findings highlight the potential application of 24-EBL as a sustainable approach for improving wheat resilience against high temperature stress.
Keywords: Wheat (Triticum aestivum L.), 24-epibrassinolide, high temperature stress, Morpho-physiological traits, Relative Water Content (RWC), Membrane Stability Index (MSI)