Physiological Modulation of Oilseed Crops by Plant Growth Regulators

Plant growth regulators (PGRs) serve as vital biochemical messengers, modulating growth, developmental transitions, and stress resilience in oilseed crops. This review synthesizes current evidence on the physiological and agronomic benefits of exogenously applied PGRs—including auxins, gibberellins, cytokinins, brassinosteroids, salicylic acid, jasmonic acid, ethylene, paclobutrazol, triacontanol, and chlormequat chloride—across sesame (Sesamum indicum L.), groundnut (Arachis hypogaea L.), sunflower (Helianthus annuus L.), mustard (Brassica juncea L.), and castor (Ricinus communis L.). Foliar and seed treatments at stage-specific concentration significantly enhanced plant height, branching, leaf area index, chlorophyll content, reproductive organ development, and yield attributes. Under abiotic stresses such as drought, salinity and heat, PGRs improved antioxidant defense, photosynthetic efficiency and assimilate partitioning, contributing to enhanced seed and oil yield stability. Synergistic applications, such as combining auxins with brassinosteroids or cytokinins, provided additive benefits in reproductive success and seed setting. The collective findings underscore the agronomic importance of integrating PGR-based strategies into oilseed crop management for improved productivity, stress mitigation, and resource-use efficiency under variable agro-climatic conditions.