Articles
EFFECTS OF CULTIVATION PRACTICES ON LEAF AREA, PHOTOSYNTHETIC RATE AND GRAPE YIELD OF CV. ‘DIMIAT’ VINES
Photosynthetic rate was determined in an open system with an infra-red gas analyser URAS-2 installed in a mobile laboratory.
It was found that positive correlation existed between the yield per vine and the row width (r2=0.7604) with semi-high training.
The relationship could be described by linear or non-linear regressions.
The yield quality was also affected by the methods of cultivation.
The increase of interrow space from 2.5 to 3.5 m, resulted in a reduced sugar content; the same effect had the elongation of the trunk.
The differences induced by the treatments were smaller than those coming from the individual years.
Largest leaf area per vine (6.27 m2) was formed at distance between the rows of 3.0 m on account of greater mean size of the leaves.
Leaf area per hectare diminished in general with the increase of interrow space.
However, leaf productivity (yield per one leaf or per unit leaf area) was highest in case of interrow space of 2.5 m (5.32 g per leaf) and lowest in case of 1.25 m (2.82 g per leaf). The photosynthetic rate increased when the space between the rows was increased, but it reached the maximum value at 2.5 m.
However, the rate of photosynthesis was affected more strongly by the training system.
Finally, positive correlations existed between the yield per vine and the photosynthetic rate, as well as between grape yield and leaf area per vine, but the commercial harvest depended also on the distribution of assimilates between reproductive and vegetative organs.