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Light environment and canopy assessment parameters within tablegrape vineyards trained to the overhead trellis in the south-central region of Chile.

Moreno, Y. M.; Pavez, J.;

Acta Horticulturae Year: 2000 Issue: No. 514 Pages: 171-177 Ref: 9 ref.

2000

บทคัดย่อ

Light environment and canopy assessment parameters within tablegrape vineyards trained to the overhead trellis in the south-central region of Chile.

The light environment within grapevine canopies is largely determined by the training/trellis system employed. These factors when combined with canopy management practices define canopy assessment parameters that have important implications on yield and quality. The light environment and leaf area relations of grapes cv. Thompson Seedless, trained to an overhead trellis in 8 commercial vineyards in Chile, were investigated. Photosynthetic active radiation (PAR), leaf area index (LAI), leaf layer number (LLN) and percentage of canopy gaps (through a point quadrant analysis) were measured. LAI was in the range 1.8-8.06. Leaf area density increased <20% between fruit set and harvest in sites having LAI <2.8 (low vigour), and increased 90-200% in sites having LAI >5. Light distribution was not uniform within the canopy as PAR levels decreased from 40 down to 5% of ambient values when measured from the periphery to centre of the plant. This differences increased as the season progressed, reaching lev

els of 1.5% ambient values during the period of veraison-harvest. In all sites, LLN averaged 4.4. Leaf area per gram of fruit averaged 16.7 cm2/g. Fruit overall quality and the incidence of postharvest disorders (waterberry and weak berries) were positively correlated to sites having high LLN, low canopy gaps and excessive growth during the veraison-harvest period.