Leaf Retention Affects Photosynthetic Activity, Leaf Area Index, Yield and Quality of Crimson Seedless Grapes

The research was conducted at ICAR-National Research Centre for Grapes, Pune during October, 2023 to March, 2024 to investigates the effect of varying leaf retention on leaf area index (LAI), photosynthetic activities, yield and quality of Crimson Seedless grapes grafted on Dogridge rootstock. Five treatments of different numbers of leaves retained on each shoot above the bunch (10, 12, 14, 16 and more than 16 leaves) were evaluated. Parameters measured included leaf area, leaf area index, photosynthetically active radiation (PAR), photosynthetic rate, stomatal conductance, chlorophyll content, average bunch weight, berry weight, yield per vine, total soluble solids (TSS) and acidity. The results showed that leaf area per leaf ranged from 140.60 cm² in the treatment with more than 16 leaves to 156.40 cm² in the 12-leaf treatment. The highest yield per vine (12.89 kg) and optimum berry quality were observed with 12 leaves above the bunch. Increased leaf area improved nutrient assimilation and berry growth but excessive leaf retention led to decreased light penetration and photosynthetic efficiency. These findings suggest that maintaining 12 leaves with 1782.70 cm2 leaf area above the bunch is optimal for balancing yield (12.89 kg/vine) and berry quality in Crimson Seedless grapes under the tropical conditions.