Logistic regression analysis of factors influencing core breakdown in 'Conference' pears

Core breakdown of 'Conference' pears (Pyrus communis L.) is characterised b y softening and browning of tissue near the core and is associated with the development of cavities. The disorder causes large economic losses of 'Con ference' pears in Belgium, stored under controlled atmospheres. Factors tha t influence development of the disorder, CO2 and O-2 concentration, the siz e and weight of the pear, the picking date and the storage temperature: wer e investigated. Multiple logistic regression was used to establish predicti on and classification models for both internal browning and cavity developm ent. Over-mature fruit was more susceptible to core breakdown during storag e. It was also found that pears with a large weight had a higher probabilit y of developing brownheart. R-2 values from 0.7 to 0.92 were obtained betwe en the predicted and measured percentages of brownheart and cavities. The m odels classified up to 86% of the Fears correctly. In a final analysis, the time sequence of the symptoms occurring during core breakdown disorder dev elopment was modelled with a generalized logits model. (C) 2000 Elsevier Sc ience B.V. All rights reserved.