|Institution:||University of Tasmania|
|Full text PDF:||http://eprints.utas.edu.au/20231/1/whole_LewisTerryLayton1957_thesis.pdf|
In recent years studies have been made of the variation in the physiology and disorder incidence of apples within a tree and between trees in one orchard, within a season and between seasons. One of the remaining problems is that of between-site variation. The existence of between-site variation is traditional, and is regarded by orchardists as considerable even when cultural treatments do not differ. For example, the fruit of the Braeside area in Southern Tasmania grown at an altitude of about 700 feet is reputed to be of superior keeping quality to that grown at the general level of the Huon Valley. Certain patterns of between-tree variation have now been established (Martin and Lewis 1952, Martin 1954a,b) which enable us to take account of some variables when making a between-site comparison. This thesis describes an attempt at such a comparison. It embodies investigations carried out in the period 1954-1956, using small plots on different sites in three localities in the Huon district of Tasmania, with a view to finding answers to the following questions: (1) Do differences between sites depart significantly from the normal between-tree variation? (2) Does fruit from high and low altitudes differ in its susceptibility to disorders? (3) If there are any site or altitude differences in disorder susceptibility are they accompanied by significant differences in the physiological characteristics of the fruit? If so, do these differences tend to confirm or deny theories developed from the between-tree studies? (4) Are there any differences in the between-site variation between seasons, and if so how far are they in line with indications from the ideas developed from other studies?