J.J. Hueso, M. González, J. Cuevas
Successful regulated deficit irrigation (RDI) strategies have been previously applied in loquat (Eriobotrya japonica Lindl.) with the main objective of advancing bloom and harvest and make loquat cultivation more profitable. In these strategies, water deficit is imposed after harvest when the period of most intense vegetative growth and greater water demand take place. The use of RDI also makes possible tree size control. Here, we report the effects of 7 years of postharvest RDI on the vegetative growth of an ‘Algerie’ orchard established in February 1992 in Almería, a semi-arid area of southeast Spain. The trial is divided in two phases. The first was carried out from the 1999/2000 to the 2001/2002 seasons on young trees at a distance of 5 x 2.5 m; the second phase started in the 2003/2004 season after removing one out of two trees. In both periods, tree canopy volume, trunk cross-sectional area (TCSA), pruning wood weight, new shoot length and number and size of the leaves were measured. Water cut was established from end of May to end of August and reached 45% of the water applied to fully irrigated trees in that period. Significant effects were observed on trunk growth; such effects accentuated with time. No diminution was detected on canopy volume. Although canopy size is annually controlled by pruning, pruning wood weight was not systematically reduced by RDI. Shoot extension was not either controlled by RDI, although the number and the size of the leaves forming during stress period were reduced some years. Productivity increased, due to the reduced trunk growth of water-stressed trees. Water use efficiency also increased. Despite moderate effects on tree size, RDI appears to be a sustainable, more profitable alternative to growth regulators for reducing vegetative growth in high density loquat orchards.
Hueso, J.J., González, M. and Cuevas, J. (2007). TREE SIZE CONTROL BY MEANS OF DEFICIT IRRIGATION IN 'ALGERIE' LOQUAT. Acta Hortic. 750, 293-298
DOI: 10.17660/ActaHortic.2007.750.46
Eriobotrya japonica, regulated deficit irrigation, vegetative growth, canopy volume, pruning wood, trunk growth

Acta Horticulturae