ENHANCING PRODUCTIVITY OF CUSTARD APPLE (cv. APK (CA) 1) THROUGH PLANT DENSITY STANDARDIZATION AND CANOPY MANAGEMENT

Abstract

A field experiment was conducted at the Regional Research Station, Tamil Nadu Agricultural University, Aruppukottai, Tamil Nadu, to standardize plant density through canopy management in custard apple. The variety APK (Ca) 1 was used as the experimental material. The trial was laid out in the C1 field. Custard apple grafts were prepared and established at the Regional Research Station, Aruppukottai. The planting of custard apple was carried out during 2004. The experiment was laid out in a Randomized Block Design (RBD) with five replications and four treatments, viz., T₁ (plant spacing of 6 m × 6 m; 36 m²), T₂ (plant spacing of 6 m × 5 m; 30 m²), T₃ (plant spacing of 6 m × 4 m; 24 m²), and T₄ (plant spacing of 6 m × 3 m; 18 m²). Observations on soil moisture content (at 15, 30, and 60 cm depths), plant height (m), stem girth (cm), number of branches, number of secondary branches, and tree spread in the north–south and east–west directions were recorded. Physiological parameters such as Chlorophyll Stability Index (CSI), Relative Water Content (RWC), proline content, and nitrate reductase enzyme activity were also measured and estimated in all treatments. The results indicated that custard apple cv. APK (Ca) 1 planted at a spacing of 6 m × 6 m recorded higher values for all morpho-physiological and biochemical parameters compared to the other high-density planting treatments under rainfed conditions. The same treatment (T₁: 6 m × 6 m) also maintained its superiority in improving yield and yield attributes, recording a higher single fruit weight (155.8 g), pulp weight (92.4 g fruit⁻¹), and fruit yield (24.7 kg tree⁻¹) than the other high-density planting treatments under rainfed conditions. Based on the results, it can be concluded that a spacing of 6 m × 6 m is highly suitable for custard apple cultivation under rainfed conditions and is recommended for obtaining the highest yield.