J.P. De Melo-Abreu, M.L. Sousa, J.S. Lopes
After some decades of experience and basic data gathering in ‘Rocha’ pear production and quality formation, we conducted four years of very detailed experiments in central Portugal. Treatments consisted of training systems and pruning levels. Experimental orchards differed in age (3 to 11 years) and planting density (2700 to 5400 trees ha-1). The data yielded by these experiments were used to construct, calibrate and validate a model to simulate potential and water-limited level of production and fruit grade, for a given range of years so it can be used as a tool for selection of training system and definition of ideal pruning level. The model inputs are parameters (location, soil physical characteristics and water content, planting distances, initial tree size and shape of the crown envelope, physiological response, biophysical and management) and weather variables. Biomass formation and partitioning, crop area formation, individual fruit growth, and water balance and its components are computed daily. Validation was done on 36 crop/years, with productivities that ranged from 23.4 to 149.9 t ha-1 and fruit numbers that ranged from 13.3 to 136.3 fruits m-2. This model is multi-year, it uses approaches valid under Mediterranean and sub-tropical environments, namely in the developmental process, carbon assimilation, potential individual fruit growth and fruit grade estimation. The time-course of simulated variables (leaf and crop area indices, dry matter (DM) in various tree compartments, water use and fruit grade) were simulated appropriately by the model, with high modelling efficiencies. The predictions of productivity and fruit numbers had modelling efficiencies of 0.68 and 0.85, respectively. If the number of fruits is known, which may be done in a real situation after fruit set, modelling efficiencies of the predictions of productivity are even higher. This model has a high performance, and may be used for research purposes and to assist fruit growers in their management decisions. Current and future work aims at reduction of input parameters and further corroboration.
De Melo-Abreu, J.P., Sousa, M.L. and Lopes, J.S. (2015). CSS_PEAR: A MODEL TO SIMULATE GROWTH, PRODUCTION AND QUALITY OF PEAR (PYRUS COMMUNIS L.). Acta Hortic. 1094, 223-231
DOI: 10.17660/ActaHortic.2015.1094.28
'Rocha', radiation interception, RUE, yield, fruit quality, fruit size distribution, relative growth rate

Acta Horticulturae