353 The Assessment of Different Rootstocks to the Pear Tree Cultivar ‘Carrick’ C.L. Giacobbo Universidade Estadual do Rio Grande do Sul UERGS - Pólo de Vacaria Rio Grande do Sul Brazil A. Gazolla Neto, D. Pazzin, P. Francescatto and J.C. Fachinello Universidade Federal de Pelotas FAEM-UFPel, Rio Grande do Sul Brazil Keywords: Pomacea, Cydonia oblonga, Pyrus spp., slender spindles, plant development Abstract Low fruiting is the main problem related to the pear production in Brazil, which makes the country one of the major pear importers. This research aimed to evaluate different rootstocks to pear tree cultivar ‘Carrick’ to be used in commercial orchards. The experiment was carried out in Pelotas/RS, located at latitude 31°52’00”S, longitude 52°21’24”W Greenwich and altitude of 13.24 m. The orchard was set up in 2002 with a density of 2000 trees.ha -1 . The trees were conducted in slender spindler system trained on three-wire support with a dripping irrigation system. The treatments assessed were 13 quince rootstocks (Cydonia oblonga) cultivars ‘Adams’, ‘Alaranjado’, ‘BA 29’, ‘Bereczcki’, ‘Champion’, ‘Du Lot’, ‘D’Vranja’, ‘EMC’, ‘Inta 267’, ‘Lageado’, ‘Melliforme’, ‘PineApple’ and ‘Portugal’ and one Pyrus calleryana. The experimental design utilized was a complete randomized block with 3 replications of 5 trees each. The variables assessed were rootstock/scion trunk diameter, tree height, canopy volume, pruning weight, productivity and productivity efficiency. ‘D’Vranja’ rootstock provided the highest vigor to the tree, whereas the rootstock cultivars ‘Du Lot’, ‘Lageado’ and ‘Bereczcki’ the lesser vigor, however not differing from most of the rootstocks in the study. The highest productivity was verified by using the rootstock ‘Portugal’ (1.12 t.ha -1 ), followed by ‘EMC’ that did not differ from ‘D’Vranja’ and ‘BA 29’. ‘D’Vranja’ showed the highest vigor and also had the highest productivity efficiency (9.53), but did not differ from ‘BA 29’. Although ‘D’Vranja’ provided more vigor to the tree, it is still a good rootstock alternative to the pear cultivar ‘Carrick’. INTRODUCTION According to the FAO (2007), the world fruit crop confirmed in 2005 a production around 507 million tons. Included in this, the European pear culture is pointed out as the ninth production country with 3.9% of the total. Italy, considered as the major producing country of the fruit, participates with 4.7% of the total, whereas Brazil has a little expressive production at about 0.11%. As regards demand for pear fruits in Brazil, the culture shows a large expansion potential. However, there are some constraints caused by the inexistence of cultivars adapted to different regions as the lack of research and indetermination of adapted rootstocks. Traditionally, the pear trees grown in the main world producing centers are grafted on quince rootstocks (Cydonia oblonga Mill.) or Pyrus communis and occasionally on Pyrus calleryana or Pyrus betulaefolia (Strydom, 1998). Nevertheless, in Brazil, it is only since 2002 that the use of quince tree as rootstock gained focus and was researched. For Marangoni (1999) the modern pear culture is trending in the use of high density planting to reduce labor costs. Therefore, some concerns at the moment of rootstock purchase must be paid attention to. According to Strydom (1998), a good rootstock must show as main characteristics compatibility to the commercial cultivars, easy propagation, tree vigor control, induce large fruits and adaptability to different climate and soil conditions. The indiscriminate use of quince rootstock, as said by Loreti (1994), has allowed Proc. 8 th IS on Temperate Zone Fruits in the Tropics and Subtropics Eds.: F.G. Herter et al. Acta Hort. 872, ISHS 2010