ISHS Acta Horticulturae 800: X International Pear Symposium
A MODEL FOR PREDICTING FRUIT GROWTH OF 'ROCHA' PEAR |
| Authors: | C.M. Rasteiro, N. Isidoro |
| Keywords: | Pyrus communis, fruit growth, logistic model, predict pear size |
| Abstract:
The pear cultivar 'Rocha' (Pyrus communis L.) is of interest to the market because of its excellent fruit quality (flavour, shelf-life and storage), and the high degree of consumer acceptance and demand. Crop management can be improved by the analysis and modelling of crop growth. Fruit growth in particular represents a relevant element because it is directly related with crop yield and thus has an important role in the economic results of the orchard. The objective of this work was to predict the fruit growth pattern of 'Rocha' pear, between full bloom and harvest, as a function of time, using an empirical mathematical model. Fruit growth of 'Rocha' was studied, under field conditions, during seven years (2000–2006), in an experimental orchard located in the West of Portugal. Every year, 120 fruits were tagged and the fruit diameter (FD) measured weekly with a Mitutoyo digital (mm); the range of sampling dates was 31 to 148 days after full bloom (DAFB). Equations were developed using the statistical package SPPS, (SPSS Inc. Chicago, IL), and model suitability was evaluated using the Levenberg-Marquardt method. The results indicate that the logistic model was able to predict pear size and was the most satisfactory fit: FD (mm) = 67.88/(1+e2.3409-0.0330*DAFB), R2 = 0.98, P<0.001. The model could be a very important tool, to advise the growers on the predicted potential final pear size, in order to decide, at the right time, the adequate management of the orchard (thinning fruit, irrigation, fertilization). | |
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