Prohexadione calcium controls shoot growth of pear trees

Abstract

The aim of this study was to evaluate the effects of prohexadione calcium (PCa) on vegetative growth and production of ‘Carrick’, ‘Packham’s’ and ‘William’s’ pear. The trial was performed at the experimental field of the Federal University of Pelotas, Capão do Leão, RS, Brazil (31º 52’ 00" S; 52º 21’ 24" W), during the growing seasons of 2011 and 2012. Treatments were applied to single-tree replications in a randomized complete block design with four replications as follows: Control (unsprayed), PCa (PCa - 750 g ha-1 i.a.). The application was split in four (187,5g ha-1 a.i. each) and three timings (250g ha-1 a.i. each) in the 2011 and 2012 growing seasons, respectively. The assessed parameters were: shoot length, trunk cross sectional area (TCSA) increment, number of nodes, internode length, pruning weight, number of fruits, average fruit weight, production per tree and return bloom. It was possible to conclude that application of PCa at 750 g. ha-1 a.i satisfactorily controls shoot growth through the reduction of internode length of ‘Carrick’, ‘Packham’s’ and ‘William’s’ pears. Besides, it was observed that return bloom is not negatively affected by PCa. So, this plant growth regulator is a potential management tool to reduce shoot growth and the need for pruning in pear orchards.