Effect of paclobutrazol, prohexadione-Ca, deficit irrigation, summer pruning and root pruning on shoot growth, yield, and return bloom, in a ‘Blanquilla’ pear orchard

During the period 2001–2003 the performance of paclobutrazol, prohexadione-Ca, root pruning, summer pruning and deficit irrigation was studied with respect to a control in a Blanquilla pear orchard. Shoot growth, yield, fruit size, and return bloom were all evaluated.Paclobutrazol was associated with the shortest shoot length and the highest return bloom. Summer pruning and prohexadione-Ca were the strategies that produced the next shortest shoot length; however, summer pruning registered the lowest return bloom and accumulated yield. Prohexadione-Ca did not have any significant negative effect on either return bloom or yield. Root pruning and deficit irrigation produced a slight reduction in shoot length, although these were, respectively, the second and third strategies in relation to return bloom.Before 2001, chlormequat chloride (CCC) was a good tool because it provided good growth control, and increased both return bloom and fruit set. The strategies studied do not present all of these benefits at the same time, but each one contributes with any advantage on growth control, return bloom, fruit set or yield.It seems than the option to optimize growth control, return bloom and yield must be pursued with the integration of several strategies