عوامل موثر تعيين بلوغ تجاري ميوه در ارقام مختلف گلابي (Pyrus communis L.)

Effective Parameters in Determination of Commercial Fruit Maturity of Different Pear {Pyrus communis L.) Cultivars

Such different factors as days following full bloom till harvest, exterior change of fruit color and percentage of soluble solids have been suggested for determining the suitable harvest time. These factors are on the other hand greatly dependent on yearly climatic factors, type of fruit, position of fruit on the tree as well as on orchard management. In this research, some of the above mentioned factors along with some other supplementary factors as change in firmness, percentage of dry material, percentage of acidity, fruit juice pH and changes of starch were comparatively investigated in a four months period during the growth season and as well during 2 months following the storage of the fruits. Nine cultivars of foreign and local pear including Spadona, Barttlet, Beyrouti, Dargazi, Dutchesse, Shah Miveh, Felestini, Coscia and Louise Bonne were studied. Percentage of soluble solids and pH of fruit juice increased while acidity of the fruits decreased in the same process. Dry material percentage of fruits was approximately stable. Therefore, the use of this index in determining the suitable fruit harvest time was impossible. The firmness of the fruits decreased and followed the same behavioral pattern in the fruits on different parts of the tree. Since starch test did not reveal significant changes, it was not considered as an effective and practical test to determine the maturity in different pear cultivars. Results showed that fruit firmness can be considered as one of the effective indices to determine commercial fruit maturity of different pear cultivars.