THE GROWTH CHARACTERISTICS OF PEAR TREES OF THE CULTIVAR 'PACKHAM'S TRIUMPH' ON DIFFERENT ROOTSTOCKS IN THE PELOTAS REGION, RS, BRAZIL

Abstract

The aim of this research was to evaluate the growth and development of pear trees of the cultivar ‘Packham’s Triumph’ grafted on six different quince rootstock cultivars, ‘Adams’, ‘Alongado’, ‘D’Angers’, ‘EMC’, ‘Portugal’ and ‘Smyrna’, and one Pyrus calleryana. The experiment was carried out at the experimental field of the Federal University of Pelotas (FAEM/UFPEL), Palma Agricultural Center, Capao do Leao, Pelotas RS, Brazil. In August 2002, the pear trees were planted at 5 x 1 m (2000 trees.ha -1 ) and trained as slender spindles on a three-wire support. A drip irrigation system was set for four hours each day (2 L/h/tree). The experimental design was a complete randomized block with three replications of four trees each. Data collected were trunk diameter, tree height, canopy volume, leaf area and fresh and dry leaf weight. In general, ‘EMC’ supported less plant development (vigour) of ‘Packham’s Triumph’, followed by ‘Portugal’. However, ‘Smyrna’, and to a slightly lesser extent, ‘Alongado’, had the better (more vigorous) plant development. The reduction in tree height, when grafted on ‘EMC’ rootstock, was 49.33% in relation to the more vigorous rootstock, ‘Smyrna’. ‘EMC’ had the largest difference among the rootstocks in trunk diameter and showed a reduced diameter of its trunk in comparison to the cultivar (0.37 mm). Moreover, ‘EMC’ induced a lesser leaf area (54.16 cm 2 ), fresh (0.01 N) and dry weight (0.01 N) in the scion, whereas ‘Smyrna’ induced greater averages of leaf area (92.13 cm 2 ), fresh (0.03 N) and dry weight (0.02 N). Some yields were obtained by using quinces rootstocks cultivars ‘D’Angers’ and ‘Smyrna’.