Bio-efficacy Studies of Unique in Relation to Growth, Yield and Shelf Life of Nanasaheb Purple Seedless Grape Variety Grown under Multilocation

Abstract

Grape production, particularly seedless varieties like Nanasaheb Purple Seedless is highly valued for both domestic and export markets. However, environmental stresses such as drought and salinity often affect the quality and yield of grapes. This study explored the effectiveness of bio-stimulant (Unique) enhancing grape yield, quality and shelf life across two locations: ICAR-NRC for Grapes, Pune and Walwa, Sangli District of Maharashtra. While, bio-stimulants have shown potential in promoting vine growth and stress resilience, there is limited research on the optimal dosage and application timing for specific varieties like Nanasaheb Purple Seedless. The primary objective of this study was to identify the most effective dose and application schedule of Unique to maximize yield, berry quality and shelf life. A randomized block design (RBD) was employed with three treatment levels (20, 25 and 30 ml/L) of Unique applied through foliar spray at five key growth stages. Growth, yield, and quality parameters were measured and compared with control. Results revealed that Unique application of 30 ml/L at five critical growth stages significantly enhanced bunch weight, berry size and yield. Additionally, biochemical markers such as phenol, protein and reducing sugar levels also increased.  Leaf area and chlorophyll content in leaf also improved facilitating better nutrient absorption and photosynthesis. Shelf life was extended with reduced weight loss during storage. The foliar application of 30 ml of Unique at specific growth stages is recommended to optimize the quality, yield and shelf life of Nanasaheb Purple Seedless grapes.