Hydrogened cyanamide promotes dormancy breakage in pear tree grown in a subtropical region

ABSTRACT

The pear tree (Pyrus spp.) is a fruit tree of temperate climate, so it needs a certain number of hours under cold temperatures to overcome its natural dormancy. It can be cultivated in the tropics, but few regions have cold enough winters to overcome the natural dormancy of pear trees. For this purpose, it is necessary to select cultivars with less need for cold conditions combined with the use of bud-inducing to sprouting and flowering products. This study aimed to test doses of hydrogenated cyanamide (Dormex) to break dormancy and induce bud sprouting in different pear cultivars under subtropical conditions. The branches of five pear tree cultivars, ‘Cascatense’, ‘Primorosa’, ‘Seleta’, ‘Packham’s Triumph’, and ‘William’s’, were sprayed with Dormex (a commercial product containing 52% hydrogen cyanamide, CH₂N₂) at 1, 2, 3, 4, or 5% or with water (control). The trees were evaluated at two, four, six, eight, 10, and 12 weeks after the application of the treatments in two consecutive years. The European pear trees ‘William’s’ and ‘Packham’s Triumph’ showed low budding rates compared to hybrid pear trees. Hybrid pear showed better performance in subtropical regions, with higher budding rates, than European pear. CH₂N₂ efficiently induces bud sprouting of pear, with especially 4 and 5% Dormex.

Key words
Pyrus spp.; Dormex; anticipation of production