ABSTRACT
The objective of this study was to determine the influence of planting space on vegetative growth of the pear trees cvs. Rocha and Hosui at different spacing under organic production system. The nursery trees grafted on quince ‘CP’ were planted in September 2009. The adopted spacing were: 1.0, 0.8, 0.6 and 0.4 m among plants with 3.5 m between rows, equivalent to planting densities of 2,857; 3,571; 4,762 and 7,143 plants ha-1, respectively. For two consecutive cycles - 2011/2012 and 2012/2013 – referent to third and fourth year after planting, respectively, it was evaluated the following: diameter of trunk, diameter of branches and number of branches. In the second cycle were evaluated the canopy volume, the estimated vertical projection of leaf area, the canopy cover and the leaf content of chlorophylls a, b and total . Considering the variables vertical projection of estimated leaf area, canopy volume and diameter of trunk and branches, the cv. Hosui showed the greatest vigor. The cv. Rocha presented decreasing chlorophyll content for the increasing in planting density, while for cv. Hosui the chlorophyll content did not vary with the reduction of plant density. There was an increase in leaf area estimated as a function of density for the two cultivars; however, for the canopy volume, this effect was observed only for cv. Hosui, nevertheless index and canopy cover only for cv. Rocha. The highest planting density was favorable for pear trees of cv. Hosui, providing greater canopy volume per area without compromising the levels of leaf chlorophyll and increased canopy cover. However, for pear trees of cv. Rocha, planting density higher than 4,700 plants ha-1, could be harmful, as it decreases the levels of leaf chlorophyll, but keeping increasing canopy cover, which may indicate self-shading.
Index terms
Pyrus Communis
;
Pyrus pyrifolia
;
Cydonia oblonga
; Planting density under organic agriculture
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