GROWTH PATTERN OF 'ABBE FETEL' PEAR FRUITS

Abstract

The pear cultivar 'Abbe Fetel' (Pyrus communis L.) is becoming of interest to the industry because of the excellent fruit quality and the high degree of consumer acceptance and demand. Therefore, size prediction is needed for harvest and marketing management. The objective of this work was to predict fruit growth of 'Abbe Fetel' as a function of time using an empirical mathematical model. Fruit growth was followed at the Experimental Farm of the Comahue National University, Rio Negro, Argentina, during the 2000-01, 2001-02 and 2002-03 growing seasons. Maximum fruit diameter (FD) measurements were carried out every two weeks (n = 535) with a Vernier caliper to the nearest 0.01 cm and the range of sampling dates was 26 and 143 days after full bloom (DFB). Equations were developed with SYSTAT procedure and model suitability was evaluated using goodness-to-fit measures. In addition, fruits were sampled in the 2003-04 growing season to test the accuracy of the models being developed. Results showed that the following logistic model provided the most satisfactory fit to the pooled data (as compared to the power and linear models): FD (mm) = 78.59/(1 + e 2.3072-0.0288 DFB) , R 2 = 0.97, p < 0.001 The testing on an independent crop showed that predictions were accurate. Consequently, the logistic function provided the best fit to predict FD. These models can assist growers with a means of determining the adequate timing of harvest, considering that unless a certain minimum size is obtained, the fruit will be given a lower grade and price.