Alterations in Leaf Metabolites and Antioxidant Defense Induced by Girdling in ‘YaLi’ Pear Under Subtropical Conditions of North‐West India

The investigations were conducted to study the impact of girdling treatments on leaf metabolic changes in low chill ‘YaLi’ pear cultivar trained under Espalier system. It focuses on leaf antioxidant defense mechanisms, accumulation of osmolytes, secondary metabolites, and their impact on vegetative growth and fruit production. Girdling treatments significantly enhanced hydroxyl and superoxide radical scavenging activities, total reducing power and the activities of antioxidant enzymes, with the greatest response observed under TG + SLG. The combined girdling treatment also resulted in the highest activities of proline metabolism enzymes, accompanied by increased accumulation of proline, choline, glycine betaine, ascorbic acid, dehydroascorbic acid, and glutathione. However, chlorophyl content, water sprout length and water sprout diameter were reduced in girdled plants. Fruit yield increased by 28.96% under TG + SLG compared with the control. Correlation and principal component analysis revealed strong positive associations between fruit yield and antioxidant defense, osmolyte accumulation, and proline metabolism, whereas vegetative growth parameters were negatively correlated with these biochemical attributes. The findings demonstrate that girdling induces metabolic reprogramming involving enhanced antioxidant protection, osmotic adjustment, and redox regulation, thereby redirecting assimilates from vegetative growth toward fruit production. These biochemical responses provide mechanistic insight into the beneficial effects of girdling and support its use as an effective canopy management strategy for improving productivity in high‐density pear orchards.