Paclobutrazol-Mediated Regulation of Growth, Physiology and Yield in Groundnut (Arachis hypogaea L.): A Review

Abstract:

Groundnut (Arachis hypogaea L.) is an important oilseed crop, yet its productivity is often constrained by excessive vegetative growth, poor source-sink balance, and suboptimal assimilate partitioning. Plant growth regulators, particularly paclobutrazol (PBZ), have emerged as effective tools to regulate plant architecture and improve yield efficiency. PBZ, a triazole-based compound, inhibits gibberellin biosynthesis by blocking ent-kaurene oxidase activity, resulting in reduced stem elongation and compact canopy formation. This physiological modification improves light interception, reduces mutual shading, and enhances radiation use efficiency. In addition, PBZ alters hormonal balance by increasing abscisic acid levels and improving stress tolerance responses. It also enhances chlorophyll content, delays senescence, and stimulates antioxidant enzyme activity, thereby improving photosynthetic efficiency and oxidative stress management. Furthermore, PBZ promotes better source-sink relationships by redirecting assimilates from vegetative to reproductive organs, leading to improved pod development, kernel weight, and harvest index. Enhanced accumulation of osmoprotectants and carbohydrates further supports plant resilience under abiotic stress conditions such as drought. Overall, PBZ contributes to improved dry matter partitioning, photosynthetic performance, and yield stability in groundnut. Although extensive research exists on PBZ in various crops, its integrated physiological and agronomic effects in groundnut remain less comprehensively synthesized. This review highlights the chemical nature, mode of action, and physiological responses of PBZ, emphasizing its potential to enhance productivity and sustainability in groundnut cultivation under changing environmental conditions.